Genetics & Rare Diseases

Zhe Han lab 2018

$2 million NIH grant to study nephrotic syndrome

Zhe Han lab 2018

A Children’s researcher has received a $2 million grant from the National Institutes of Health (NIH) to study nephrotic syndrome in Drosophila, a basic model system that has revealed groundbreaking insights into human health. The award for Zhe Han, Ph.D., an associate professor in Children’s Center for Genetic Medicine Research, is believed to be the first ever NIH Research Project grant (R01)  to investigate glomerular kidney disease using Drosophila. Nephrotic syndrome is mostly caused by damage of glomeruli, so it is equivalent to glomerular kidney disease.

“Children’s National leads the world in using Drosophila to model human kidney diseases,” Han says.

In order to qualify for the five-year funding renewal, Han’s lab needed to successfully accomplish the aims of its first five years of NIH funding.  During the first phase of funding, Han established that nephrocytes in Drosophila serve the same functions as glomeruli in humans, and his lab created a series of fly models that are relevant for human glomerular disease.

“Some 85 percent of the genes known to be involved in nephrotic syndrome are conserved from the fly to humans. They play similar roles in the nephrocyte as they play in the podocytes in human kidneys,” he adds.

Pediatric nephrotic syndrome is a constellation of symptoms that indicate when children’s kidneys are damaged, especially the glomeruli, units within the kidney that filter blood. Babies as young as 1 year old can suffer proteinuria, which is characterized by too much protein being released from the blood into the urine.

“It’s a serious disease and can be triggered by environmental factors, taking certain prescription medicines or inflammation, among other factors.  Right now, that type of nephrotic syndrome is mainly treated by steroids, and the steroid treatment works in many cases,” he says.

However, steroid-resistant nephrotic syndrome occurs primarily due to genetic mutations that affect the kidney’s filtration system: These filters are either broken or the protein reabsorption mechanism is disrupted.

“When genetics is to blame, we cannot turn to steroids. Right now there is no treatment. And many of these children are too young to be considered for a kidney transplant,” he adds. “We have to understand exactly which genetic mutation caused the disease in order to develop a targeted treatment.”

With the new funding, Han will examine a large array of genetic mutations that cause nephrotic syndrome. He’s focusing his efforts on genes involved in the cytoskeleton, a network of filaments and tubules in the cytoplasm of living cells that help them to maintain shape and carry out important functions.

“Right now, we don’t really understand the cytoskeleton of podocytes – highly specialized cells that wrap around the capillaries of the glomerulus – because podocytes are difficult to access. To change a gene requires time and considerable effort in other experimental models. However, changing genes in Drosophila is very easy, quick and inexpensive. We can examine hundreds of genes involving the cytoskeleton and see how changing those genes affect kidney cell function,” he says.

Han’s lab already found that Coenzyme Q10, one of the best-selling nutrient supplements to support heart health also could be beneficial for kidney health. For the cytoskeleton, he has a different targeted medicine in mind to determine whether Rho inhibitors also could be beneficial for kidney health for patients with certain genetic mutations affecting their podocyte cytoskeleton.

“One particular aim of our research is to use the same strategy as we employed for the Coq2 gene to generate a personalized fly model for patients with cytoskeleton gene mutations and test potential target drugs, such as Rho inhibitors.” Han added. “As far as I understand, this is where the future of medicine is headed.”

DNA Molecule

Test your knowledge of APOL1’s role in kidney health

Zhe Han

$3 million NIH grant to study APOL1 and HIV synergy

Zhe Han

Zhe Han, Ph.D., (pictured) and Patricio E. Ray, M.D., have received a $3 million, five-year grant from the National Institutes of Health to study the mechanisms behind APOL1 and HIV nephropathies in children, using a combination of Drosophila models, cultured human podocytes and a preclinical model.

Two Children’s researchers have received a $3 million, five-year grant from the National Institutes of Health (NIH) to study the mechanisms of APOL1 and HIV nephropathies in children, using a combination of Drosophila models, cultured human podocytes and a preclinical model.

The APOL1 genetic variants G1 and G2, found almost exclusively in people of African ancestry, lead to a four-fold higher risk of end-stage kidney disease. HIV infection alone also increases the risk of kidney disease but not significantly. However, HIV-positive people who also carry the APOL1 risk alleles G1 or G2 are about 30 times more likely to develop HIV-nephropathy (HIVAN) and chronic kidney disease.

For more than 25 years, Children’s pediatric nephrology program has studied HIV/renal diseases and recently developed Drosophila APOL1-G0 and G1 transgenic lines. That pioneering research suggests that HIV-1 acts as a “second hit,” precipitating HIV-renal disease in children by infecting podocytes through a mechanism that increases expression of the APOL1-RA beyond toxic thresholds.

With this new infusion of NIH funding, labs led by Zhe Han, Ph.D., and Patricio E. Ray, M.D., will determine the phenotype of Drosophila Tg lines that express APOL1-G0/G1/G2 and four HIV genes in nephrocytes to assess how they affect structure and function. The teams also will determine whether APOL1-RA precipitates the death of nephrocytes expressing HIV genes by affecting autophagic flux.

“Our work will close a critical gap in understanding about how HIV-1 interacts with the APOL1 risk variants in renal cells to trigger chronic kidney disease, and we will develop the first APOL1/HIV transgenic fly model to explore these genetic interactions in order to screen new drugs to treat these renal diseases,” says Dr. Ray, a Children’s nephrologist.

While a large number of people from Africa have two copies of APOL1 risk alleles, they do not necessarily develop kidney disease. However, if a patient has two copies of APOL1 risk alleles and is HIV-positive, they almost certainly will develop kidney disease.

Patricio Ray

“Our work will close a critical gap in understanding about how HIV-1 interacts with the APOL1 risk variants in renal cells to trigger chronic kidney disease, and we will develop the first APOL1/HIV transgenic fly model to explore these genetic interactions in order to screen new drugs to treat these renal diseases,” says Dr. Ray, a Children’s nephrologist.

“Many teams want to solve the puzzle of how APOL1 and HIV synergize to cause kidney failure,” says Han, associate professor in Children’s Center for Genetic Medicine Research. “We are in the unique position of combining a powerful new kidney disease model system, Drosophila, with long-standing human podocyte and HIVAN studies.”

The team hypothesizes that even as an active HIV infection is held in check by powerful new medicines, preventing the virus from proliferating or infecting new cells, HIV can act as a Trojan horse by making the human cells it infects express HIV protein.

To investigate this hypothesis, the team will create a series of fly models, each expressing a major HIV protein, and will test the genetic interaction between these HIV genes with APOL1. Similar studies also will be performed using cultured human podocytes. Identified synergy will be studied further using biochemical and transcription profile analyses.

“Drosophila is a basic model system, but it has been used to make fundamental discoveries, including genetic control of how the body axes is determined and how the biological clock works – two studies that led to Nobel prizes,” Han adds. “I want to use the fly model to do something close to human disease. That is where my research passion lies.”

Stat Madness 2019

Vote for Children’s National in STAT Madness

Stat Madness 2019

Children’s National Health System has been selected to compete in STAT Madness for the second consecutive year. Our entry for the bracket-style competition is “Sensitive liquid biopsy platform to detect tumor-released mutated DNA using patient blood and CSF,” a new technique that will allow kids to get better treatment for an aggressive type of pediatric brain tumor.

In 2018, Children’s first-ever STAT Madness entry advanced through five brackets in the national competition and, in the championship round, finished second. That innovation, which enables more timely diagnoses of rare diseases and common genetic disorders, helping to improve kids’ health outcomes around the world, also was among four “Editor’s Pick” finalists, entries that spanned a diverse range of scientific disciplines.

“Children’s National researchers collaboratively work across divisions and departments to ensure that innovations discovered in our laboratories reach clinicians in order to improve patient care,” says Mark Batshaw, M.D., Children’s Executive Vice President, Chief Academic Officer and Physician-in-Chief. “It’s gratifying that Children’s multidisciplinary approach to improving the lives of children with brain tumors has been included in this year’s STAT Madness competition.”

Pediatric brain cancers are the leading cause of cancer-related death in children younger than 14. Children with tumors in their midline brain structures have the worst outcomes, and kids diagnosed with diffuse midline gliomas, including diffuse intrinsic pontine glioma, have a median survival of just 12 months.

“We heard from our clinician colleagues that many kids were coming in and their magnetic resonance imaging (MRI) suggested a particular type of tumor. But it was always problematic to identify the tumor’s molecular subtype,” says Javad Nazarian, Ph.D., MSC, a principal investigator in Children’s Center for Genetic Medicine Research. “Our colleagues wanted a more accurate measure than MRI to find the molecular subtype. That raised the question of whether we could actually look at their blood to determine the tumor subtype.”

Children’s liquid biopsy, which remains at the research phase, starts with a simple blood draw using the same type of needle as is used when people donate blood. When patients with brain tumors provide blood for other laboratory testing, a portion of it is used for the DNA detective work. Just as a criminal leaves behind fingerprints, tumors shed telltale clues in the blood. The Children’s team searches for the histone 3.3K27M (H3K27M), a mutation associated with worse clinical outcomes.

“With liquid biopsy, we were able to detect a few copies of tumor DNA that were hiding behind a million copies of healthy DNA,” Nazarian says. “The blood draw and liquid biopsy complement the MRI. The MRI gives the brain tumor’s ZIP code. Liquid biopsy gives you the demographics within that ZIP code.”

Working with collaborators around the nation, Children’s National continues to refine the technology to improve its accuracy. The multi-institutional team published findings online Oct. 15, 2018, in Clinical Cancer Research.

Even though this research technique is in its infancy, the rapid, cheap and sensitive technology already is being used by people around the globe.

“People around the world are sending blood to us, looking for this particular mutation, H3K27M, ” says Lindsay B. Kilburn, M.D., a Children’s neuro–oncologist, principal investigator at Children’s National for the Pacific Pediatric Neuro-Oncology Consortium, and study co-author. “In many countries or centers, children do not have access to teams experienced in taking a biopsy of tumors in the brainstem, they can perform a simple blood draw and have that blood processed and analyzed by us. In only a few days, we can provide important molecular information on the tumor subtype previously only available to patients that had undergone a tumor biopsy.”

“With that DNA finding, physicians can make more educated therapeutic decisions, including prescribing medications that could not have been given previously,” Nazarian adds.

The STAT Madness round of 64 brackets opened March 4, 2019, and the championship round voting concludes April 5 at 5 p.m. (EST).

In addition to Nazarian and Dr. Kilburn, study co-authors include Eshini Panditharatna, Madhuri Kambhampati, Heather Gordish-Dressman, Ph.D., Suresh N. Magge, M.D., John S. Myseros, M.D., Eugene I. Hwang, M.D. and Roger J. Packer, M.D., all of Children’s National; Mariam S. Aboian, Nalin Gupta, Soonmee Cha, Michael Prados and Co-Senior Author Sabine Mueller, all of University of California, San Francisco; Cassie Kline, UCSF Benioff Children’s Hospital; John R. Crawford, UC San Diego; Katherine E. Warren, National Cancer Institute; Winnie S. Liang and Michael E. Berens, Translational Genomics Research Institute; and Adam C. Resnick, Children’s Hospital of Philadelphia.

Financial support for the research described in the report was provided by the V Foundation for Cancer Research, Goldwin Foundation, Pediatric Brain Tumor Foundation, Smashing Walnuts Foundation, The Gabriella Miller Kids First Data Resource Center, Zickler Family Foundation, Clinical and Translational Science Institute at Children’s National under award 5UL1TR001876-03, Piedmont Community Foundation, Musella Foundation for Brain Tumor Research, Matthew Larson Foundation, The Lilabean Foundation for Pediatric Brain Cancer Research, The Childhood Brain Tumor Foundation, the National Institutes of Health and American Society of Neuroradiology.

DNA

International collaboration discovers new cause for dwarfism

DNA

An international collaboration resulted in the identification of a new cause of dwarfism: mutations in a gene known as DNMT3A.

Beyond diabetes, short stature is the most common reason for children in the U.S. to visit an endocrinologist. For the vast majority of children with short stature, the cause remains unknown – even though many of these conditions stem from an as-yet unidentified genetic cause, says Andrew Dauber, M.D., M.M.Sc., division chief of Endocrinology at Children’s National Health System.

“Parents are concerned about why their child isn’t growing and if there are other complications or health problems they’ll need to watch out for,” he says. “Without a diagnosis, it’s very hard to answer those questions.”

Dauber’s research focuses on using cutting-edge genetic techniques to unravel the minute differences in DNA that limit growth. This research recently led him and his colleagues to identify a new cause of dwarfism: mutations in a gene known as DNMT3A. The discovery, which the team published in the January 2019 Nature Genetics, didn’t happen in isolation – it required a rich collaboration of labs spread across the world in Scotland, Spain, France and New Zealand, in addition to Dauber’s lab in the U.S.

The journey that brought Dauber into this group effort got its start with a young patient in Spain. The boy, then four years old, was at less than 0.1 percentile on the growth curve for height with a very small head circumference and severe developmental delays. This condition, known as microcephalic dwarfism, is incredibly rare and could stem from one of several different genetic causes. But his doctors didn’t know the reason for this child’s specific syndrome.

To better understand this condition, Dauber used a technique known as whole exome sequencing, a method that sequences all the protein-coding regions in an individual’s entire genome. He found a mutation in DNMT3A – a change known as a de novo missense mutation, meaning that the mutation happened in a single letter of the boy’s genetic code in a way that hadn’t been inherited from his parents. But although this mutation was clear, its meaning wasn’t. The only clue that Dauber had as to DNMT3A’s function was that he’d read about overgrowth syndromes in which the function of this gene is lost, leading to large individuals with large heads, the exact opposite of this patient’s condition.

To gather more information, Dauber reached out to Andrew Jackson, Ph.D., a researcher who studies human genes for growth at the University of Edinburgh in Scotland. Coincidentally, Jackson had already started studying this gene after two patients with a shared mutation in a neighboring letter in the genetic code – who also had short stature and other related problems – were referred to him.

Dauber and his colleagues sent the results from their genetic analysis back across the Atlantic to Jackson’s Edinburgh lab, and the doctors from Spain sent more information to Jackson’s lab, including the patient’s clinical information, blood samples and skin biopsy samples. Then the whole team of collaborators from around the globe set to work to discover the processes influencing short stature in each of these three patients.

Their results showed that these mutations appear to cause a gain of function in DNMT3A. This gene codes for a type of enzyme known as a methyltransferase, which places methyl groups on other genes and on the protein spools called histones that DNA wraps around. Each of these functions changes how cells read the instructions encoded in DNA. While the mutations that cause the overgrowth syndromes appear to allow stem cells to keep dividing long past when they should taper off and differentiate into different cell types – both normal processes in development – the gain of function that appears to be happening in these three patients prompts the opposite situation: Stem cells that should be dividing for a long time during development stop dividing and differentiate earlier, leading to smaller individuals with far fewer cells overall.

The researchers confirmed their findings by inserting one of the gain-of-function human DNMT3A mutations into a mouse, leading to short animals with small heads.

Eventually, says Dauber, these findings could help lead to new treatments for this and other types of dwarfism that act on these genetic pathways and steer them toward normal growth. These and other scientific discoveries hinge on the type of international collaboration that he and his colleagues engaged in here, he adds – particularly for the types of rare genetic syndromes that affect the patients that he and his colleagues study. With only a handful of individuals carrying mutations in certain genes, it’s increasingly necessary to combine the power of many labs to better understand the effects of these differences and how doctors might eventually intervene.

“The expertise for all aspects of any single research project is rarely centered in one institution, one city, or even one country,” Dauber says. “Often, you really need to reach out to people with different areas of expertise around the world to make these types of new discoveries that can have pivotal impacts on human health.”

Vittorio Gallo

Neurodevelopmental disorders: Developing medical treatments

Vittorio Gallo

Vittorio Gallo, Ph.D., Chief Research Officer, participates in the world’s largest general scientific gathering, leading panelists in a timely conversation about progress made so far with neurodevelopmental disorders and challenges that lie ahead.

The human brain is the body’s operating system. Imagine if rogue code worked its way into its hardware and software, delaying some processes, disrupting others, wreaking general havoc.

Neurodevelopmental disorders are like that errant code. They can occur early in life and impact brain development for the rest of the person’s life. Not only can fundamental brain development go awry, processes that refine the brain also can become abnormal, creating a double neural hit.  Adding to those complications, children with neurodevelopmental disorders like autism spectrum disorder (ASD) and Fragile X syndrome often contend with multiple, overlapping cognitive impairments and learning disabilities.

The multiple layers of complexities for these disorders can make developing effective medical treatments particularly challenging, says Vittorio Gallo, Ph.D., Chief Research Officer at Children’s National Health System and recipient of a coveted Senator Jacob Javits Award in the Neurosciences.

During the Feb. 16, 2019, “Neurodevelopmental Disorders: Developing Medical Treatments” symposium, Gallo will guide esteemed panelists in a timely conversation about progress made so far and challenges that lie ahead during the AAAS Annual Meeting in Washington, the world’s largest general scientific gathering.

“This is a very important symposium; we’re going to put all of the open questions on the table,” says Gallo. “We’re going to present a snapshot of where the field is right now: We’ve made incredible advances in developmental neuroscience, neonatology, neurology, diagnostic imaging and other related fields. The essential building blocks are in place. Where are we now in developing therapeutics for these complex disorders?”

For select disorders, many genes have been identified, and each new gene has the potential to become a target for improved therapies. However, for other neurodevelopmental disorders, like ASD, an array of new genes continue to be discovered, leaving an unfinished picture of which genetic networks are of most importance.

Gallo says the assembled experts also plan to explore major research questions that remain unanswered as well as how to learn from past experiences to make future studies more powerful and insightful.

“One topic up for discussion will be new preclinical models that have the potential to help in identifying specific mechanisms that cause these disorders. A combination of genetic, biological, psychosocial and environmental risk factors are being combined in these preclinical models,” Gallo says.

“Our studies of the future need to move beyond describing and observing in order to transform into studies that establish causality between the aberrant developmental processes and these constellations of neurodevelopmental disorders.”

dystrophin protein

Experimental drug shows promise for slowing cardiac disease and inflammation

dystrophin protein

Duchenne muscular dystrophy (DMD) is caused by mutations in the DMD gene, which provides instructions for making dystrophin, a protein found mostly in skeletal, respiratory and heart muscles.

Vamorolone, an experimental medicine under development, appears to combine the beneficial effects of prednisone and eplerenone – standard treatments for Duchenne muscular dystrophy (DMD) – in the heart and muscles, while also showing improved safety in experimental models. The drug does so by simultaneously targeting two nuclear receptors important in regulating inflammation and cardiomyopathy, indicates a small study published online Feb. 11, 2019, in Life Science Alliance.

DMD is a progressive X-linked disease that occurs mostly in males. It is characterized by muscle weakness that worsens over time, and most kids with DMD will use wheelchairs by the time they’re teenagers. DMD is caused by mutations in the DMD gene, which provides instructions for making dystrophin, a protein found mostly in skeletal, respiratory and heart muscles.

Cardiomyopathy, an umbrella term for diseases that weaken the heart, is a leading cause of death for young adults with DMD, causing up to 50 percent of deaths in patients who lack dystrophin. A collaborative research team co-led by Christopher R. Heier, Ph.D., and Christopher F. Spurney, M.D., of Children’s National Health System, is investigating cardiomyopathy in DMD. They find genetic dystrophin loss provides “a second hit” for a specific pathway that worsens cardiomyopathy in experimental models of DMD.

“Some drugs can interact with both the mineralocorticoid receptor (MR) and glucocorticoid receptor (GR) since these two drug targets evolved from a common ancestor. However, we find these two drug targets can play distinctly different roles in heart and skeletal muscle. The GR regulates muscle inflammation, while the MR plays a key role in heart health,” says Heier, an assistant professor at Children’s National and lead study author. “In our study, the experimental drug vamorolone safely targets both the GR to treat chronic inflammation and the MR to treat the heart.”

After gauging the efficacy of various treatments in test tubes, the study team looked at whether any could mitigate negative impacts of the MR on heart health. Wild type and mdx experimental models were implanted with pumps that activated the MR. These models also received a daily oral MR antagonist (or inhibitor) drug, and either eplerenone, spironolactone or vamorolone. Of note:

  • MR activation increased kidney size and caused elevated blood pressure (hypertension).
  • Treatment with vamorolone maintained normal kidney size and prevented hypertension.
  • MR activation increased mdx heart mass and fibrosis. Vamorolone mitigated these changes.
  • MR activation decreased mdx heart function, while vamorolone prevented declines in function.
  • Daily prednisone caused negative MR- and GR-mediated side effects, such as hyperinsulinemia, whereas vamorolone safely improved heart function without these side effects.

“These findings have the potential to help current and future patients,” Heier says. “Clinicians already prescribe several of these drugs. Our new data support the use of MR antagonists such as eplerenone in protecting DMD hearts, particularly if patients take prednisone. The experimental drug vamorolone is currently in Phase IIb clinical trials and is particularly exciting for its unique potential to simultaneously treat chronic inflammation and heart pathology with improved safety.”

In addition to Heier and senior author Spurney, study co-authors include Qing Yu, Alyson A. Fiorillo, Christopher B. Tully, Asya Tucker and Davi A. Mazala, all of Children’s National; Kitipong Uaesoontrachoon and Sadish Srinivassane, AGADA Biosciences Inc.; and Jesse M. Damsker, Eric P. Hoffman and Kanneboyina Nagaraju, ReveraGen BioPharma.

Financial support for research described in this report was provided by Action Duchenne; the Clark Charitable Foundation; the Department of Defense under award W81XWH-17-1-047; the Foundation to Eradicate Duchenne; the Intellectual and Developmental Disabilities Research Center under award U54HD090257 (through the National Institutes of Health’s (NIH) Eunice Kennedy Shriver National Institute of Child Health and Human Development); and the NIH under awards K99HL130035, R00HL130035, L40AR068727 and T32AR056993.

Financial disclosure:  Co-authors employed by ReveraGen BioPharma were involved in creating this news release.

schistosome blood fluke

Therapy derived from parasitic worms downregulates proinflammatory pathways

schistosome blood fluke

A therapy derived from the eggs of the parasitic Schistosoma helps to protect against one of chemotherapy’s debilitating side effects by significantly downregulating major proinflammatory pathways, reducing inflammation.

A therapy derived from the eggs of parasitic worms helps to protect against one of chemotherapy’s debilitating side effects by significantly downregulating major proinflammatory pathways and reducing inflammation, indicates the first transcriptome-wide profiling of the bladder during ifosfamide-induced hemorrhagic cystitis.

The experimental model study findings were published online Feb. 7, 2019, in Scientific Reports.

With hemorrhagic cystitis, a condition that can be triggered by anti-cancer therapies like the chemotherapy drug ifosfamide and other oxazaphosphorines, the lining of the bladder becomes inflamed and begins to bleed. Existing treatments on the market carry their own side effects, and the leading therapy does not treat established hemorrhagic cystitis.

Around the world, people can become exposed to parasitic Schistosoma eggs through contaminated freshwater. Once inside the body, the parasitic worms mate and produce eggs; these eggs are the trigger for symptoms like inflammation. To keep their human hosts alive, the parasitic worms tamp down excess inflammation by secreting a binding protein with anti-inflammatory properties.

With that biological knowledge in mind, a research team led by Michael H. Hsieh, M.D., Ph.D., tested a single dose of IPSE, an Interleukin-4 inducing, Schistosoma parasite-derived anti-inflammatory molecule and found that it reduced inflammation, bleeding and urothelial sloughing that occurs with ifosfamide-related hemorrhagic cystitis.

In this follow-up project, experimental models were treated with ifosfamide to learn more about IPSE’s protective powers.

The preclinical models were given either saline or IPSE before the ifosfamide challenge. The bladders of the experimental models treated with ifosfamide had classic symptoms, including marked swelling (edema), dysregulated contraction, bleeding and urothelial sloughing. In contrast, experimental models “pre-treated” with IPSE were shielded from urothelial sloughing and inflammation, the study team found.

Transcriptional profiling of the experimental models’ bladders found the IL-1-B TNFa-IL-6 proinflammatory cascade via NFkB and STAT3 pathways serving as the key driver of inflammation. Pretreatment with IPSE slashed the overexpression of Il-1b, Tnfa and Il6 by 50 percent. IPSE drove significant downregulation of major proinflammatory pathways, including the IL-1-B TNFa-IL-6 pathways, interferon signaling and reduced (but did not eliminate) oxidative stress.

“Taken together, we have identified signatures of acute-phase inflammation and oxidative stress in ifosfamide-injured bladder, which are reversed by pretreatment with IPSE,” says Dr. Hsieh, a urologist at Children’s National Health System and the study’s senior author. “These preliminary findings reveal several pathways that could be therapeutically targeted to prevent ifosfamide-induced hemorrhagic cystitis in humans.”

When certain chemotherapy drugs are metabolized by the body, the toxin acrolein is produced and builds up in urine. 2-mercaptoethane sulfonate Na (MESNA) binds to acrolein to prevent urotoxicity. By contrast, IPSE targets inflammation at the source, reversing inflammatory changes that damage the bladder.

“Our work demonstrates that there may be therapeutic potential for naturally occurring anti-inflammatory molecules, including pathogen-derived factors, as alternative or complementary therapies for ifosfamide-induced hemorrhagic cystitis,” Dr. Hsieh adds.

In addition to Dr. Hsieh, study co-authors include Lead Author Evaristus C. Mbanefo and Rebecca Zee, Children’s National; Loc Le, Nirad Banskota and Kenji Ishida, Biomedical Research Institute; Luke F. Pennington and Theodore S. Jardetzky, Stanford University; Justin I. Odegaard, Guardant Health; Abdulaziz Alouffi, King Abdulaziz City for Science & Technology; and Franco H. Falcone, University of Nottingham.

Financial support for the research described in this report was provided by the Margaret A. Stirewalt Endowment, the National Institute of Diabetes and Digestive and Kidney Diseases under award R01DK113504, the National Institute of Allergy and Infectious Diseases under award R56AI119168 and a Urology Care Foundation Research Scholar Award.

mitochondria

Treating nephrotic-range proteinuria with tacrolimus in MTP

mitochondria

Mitochondria are the cell’s powerplants and inside them the MTP enzymatic complex catalyzes three steps in beta-oxidation of long-chain fatty acids.

In one family, genetic lightning struck twice. Two sisters were diagnosed with mitochondrial trifunctional protein (MTP) deficiency. This is a rare condition that stops the body from converting fats to energy, which can lead to lactic acidosis, recurrent breakdown of muscle tissue and release into the bloodstream (rhabdomyolysis), enlarged heart (cardiomyopathy) and liver failure.

Mitochondria are the cell’s powerplants and inside them the MTP enzymatic complex catalyzes three steps in beta-oxidation of long-chain fatty acids. MTP deficiency is so rare that fewer than 100 cases have been reported in the literature says Hostensia Beng, M.D., who presented an MTP case study during the American Society of Nephrology’s Kidney Week.

The 7-month-old girl with known MTP deficiency arrived at Children’s National lethargic with poor appetite. Her laboratory results showed a low corrected serum calcium level, elevated CK level and protein in the urine (proteinuria) at a nephrotic range. The infant was treated for primary hypoparathyroidism and rhabdomyolysis.

Even though the rhabdomyolysis got better, the excess protein in the girl’s urine remained at worrisome levels. A renal biopsy showed minimal change disease and foot process fusion. And electron microscopy revealed shrunken, dense mitochondria in visceral epithelial cells and endothelium.

“We gave her tacrolimus, a calcineurin inhibitor that we are well familiar with because we use it after transplants to ensure patient’s bodies don’t reject the donated organ. By eight months after treatment, the girl’s urine protein-to-creatinine (uPCR) ratio was back to normal. At 35 months, that key uPCR measure rose again when tacrolimus was discontinued. When treatment began again, uPCR was restored to normal levels one month later,” Dr. Beng says.

The girl’s older sister also shares the heterozygous deletion in the HADHB gene, which provides instructions for making MTP. That missing section of the genetic how-to guide was predicted to cause truncation and loss of long-chain-3-hydroxyacl CoA dehydrogenase function leading to MTP deficiency.

The older sister was diagnosed with nephrotic syndrome and having scar tissue in the kidney’s filtering unit (focal segmental glomerulosclerosis) when she was 18 months old. By contrast, she developed renal failure and progressed to end stage renal disease at 20 months of age.

“Renal involvement has been reported in only one patient with MTP deficiency to date, the older sister of our patient,” Dr. Beng adds.

Podocytes are specialized cells in the kidneys that provide a barrier, preventing plasma proteins from leaking into the urine. Podocytes, however, need energy to function and are rich in mitochondria.

“The proteinuria in these two sisters may be related to their mitochondrial dysfunction. Calcineurin inhibitors like tacrolimus have been reported to reduce proteinuria by stabilizing the podocyte actin cytoskeleton. Tacrolimus was an effective treatment for our patient, who has maintained normal renal function, unlike her sister,” Dr. Beng says.

American Society of Nephrology’s Kidney Week presentation

  • “Treatment of nephrotic-range proteinuria with tacrolimus in mitochondrial trifunctional protein deficiency

Hostensia Beng, M.D., lead author; Asha Moudgil, M.D., medical director, transplant, and co-author; Sun-Young Ahn, M.D., MS, medical director, nephrology inpatient services, and senior author, all of Children’s National Health System.

little girl with spina bifida

Oral clefts may stem from a shared genetic cause as neural tube defects

little girl with spina bifida

Research by an international team that includes Children’s National faculty, published online Jan. 25, 2019 in Human Molecular Genetics, suggests that genetic mutations that cause cleft lip and palate also may contribute to neural tube defects, such as spina bifida.

Oral clefts are some of the most common birth defects worldwide, affecting about one in every 700 births. In the U.S., more than 4,000 babies are born each year with cleft lip, with or without cleft palate.

This defect isn’t simply a cosmetic manner: Oral clefts can severely affect feeding, speech and hearing, and they cause about 3,300 deaths annually worldwide.

To better understand these conditions, researchers have isolated a number of genetic mutations that appear to play contributing roles. These include those in a gene known as Interferon Regulatory Factor 6. New research by an international team that includes Children’s National faculty, published online Jan. 25, 2019 in Human Molecular Genetics, suggests that these mutations also may contribute to neural tube defects such as spina bifida.

In the first weeks of fetal development, the neural plate curves, creating a neural tube that, once fused shut, becomes the fetal brain and fetal spinal cord. Neural tube defects, which can range from mild to severe, are characterized by incomplete development of the brain, spinal cord or meninges. These defects can potentially result in paralysis or even fetal or neonatal demise. According to the National Institutes of Health, spina bifida, which affects the spinal cord, is the most common neural tube defect in the U.S., affecting up to 2,000 infants each year.

“Despite its high frequency, spina bifida remains among the least understood structural birth defects,” says Brian C. Schutte, an associate professor of Microbiology and Molecular Genetics, Pediatrics and Human Development at Michigan State University and the study’s senior author. “There is strong evidence that genetic factors are a leading cause of such structural birth defects, but in most cases, the cause is unknown. Our team’s study is the first published research to demonstrate that DNA variants in the gene IRF6 can cause spina bifida,” Schutte says.

What’s more, the research team identified a mechanism to explain how altering IRF6 leads to neural tube defects. This mechanism links IRF6 function to two other genes – known as transcription Factor AP2A (TFAP2A) and Grainyhead Like 3 (GRHL3) – that are also known to be required for the development of the neural tube, lip and palate.

“We’re all on the hunt for the reasons when, how and why birth defects happen,” adds Youssef A. Kousa, MS, D.O., Ph.D., a clinical fellow in the Division of Child Neurology at Children’s National Health System and the study’s lead author. “Our main goal is prevention. This paper is a significant development because our team has identified a group of genes that can potentially contribute to very common types of birth defects: craniofacial as well as neural tube defects.”

The scientific odyssey is a wonderful example of serendipity. Kousa, then working in Schutte’s lab, was studying the effects of a new mutant experimental model strain on development of the palate. But one day, he walked into Schutte’s office holding a deformed preclinical embryo and said: “Brian, look at this!”

“Weird things happen in biology,” Schutte replied and counseled him to return if it happened again. Less than two weeks later, Kousa was back with several more of the deformed preclinical embryos, saying: “OK, Brian. It happened again.”

Within hours Kousa had unearthed recently published research that included an image of a similarly affected preclinical embryo. The pair then sketched out possible intersecting genetic pathways, as they brainstormed the myriad ways to end up with that specific phenotype. Initially, they tested their hypotheses in experimental models and eventually corroborated findings through human genetic studies.

The human studies could only be performed by collaborations. Schutte shared their initial observations with human genetics researchers scattered across the country. Those labs then generously agreed to test whether DNA variants in IRF6 were associated with neural tube defects in samples from patients that they had collected over decades of research.

The team found that Tfap2a, Irf6 and Grhl3 are components of a gene regulatory network required for neurulation, a folding process that results in the neural tube bending and then fusing to become the basis of the embryo’s nervous system, from brain to spinal cord.

“Since this network is also required for formation of the lip, palate, limbs and epidermis, which develop at different times and places during embryogenesis, we suggest that the Tfap2a–Irf6–Grhl3 network is a fundamental pathway for multiple morphogenetic processes,” the researchers write.

Interferon Regulatory Factor 6 functions best when there is neither too much expression nor too little. Overexpression of Irf6 suppresses Transcription Factor Activation Protein 2A and Grainyhead Like 3, causing exencephaly, a neural tube defect characterized by the brain being located outside of the skull. Counterintuitively, experimental models that had too little Irf6 also ended up with reduced levels of Tfap2a and Grhl3 that led to a structural birth defect, but at the opposite end of the neural tube.

To test whether the experimental model findings held true in humans, they sequenced samples from people who had spina bifida and anencephaly – the rare birth defect that Kousa spotted in the experimental models – and found IRF6 function was conserved in people. Because of the genetic complexity of these birth defects, and the challenges inherent in collecting samples from cases of severe birth defects, many research teams were invited to participate in the study.

As testament to their collegiality, researchers from Stanford University, University of Texas at Austin, University of Iowa, University of Texas at Houston and Duke University agreed to share precious samples from the California Birth Defects Monitoring Program, from the Hereditary Basis of Neural Tube Defects study and from their own institutional sample collections.

“As we get better at personalized medicine, we could use this information to one day help to counsel families about their own risk and protective factors,” Kousa adds. “If we can identify the genetic pathway, we might also be able to modify it to prevent a birth defect. For example, prenatal supplementation with folic acid has led to a decrease in babies born with neural tube defects, but not all neural tube defects are sensitive to folic acid. This knowledge will help us develop individual-based interventions.”

Financial support for the research covered in this post was provided by the National Institutes of Health under grants DE13513, F31DE022696, DE025060, P01HD067244 and GM072859; startup funding from Michigan State University and the UT-Health School of Dentistry in Houston; and the Centers for Disease Control and Prevention under award number 5U01DD001033.

In addition to Kousa and Schutte, study co-authors include Huiping Zhu, Yunping Lei and Richard H. Finnell, University of Texas at Austin; Walid D. Fakhouri, University of Texas Health Science Center at Houston; Akira Kinoshita, Nagasaki University; Raeuf R. Roushangar, Nicole K. Patel, Tamer Mansour, Arianna L. Smith, and Dhruv B. Sharma, Michigan State University; A.J. Agopian and Laura E. Mitchell, University of Texas School of Public Health; Wei Yang and Gary M. Shaw, Stanford University School of Medicine; Elizabeth J. Leslie, Emory University; Xiao Li, Tamara D. Busch, Alexander G. Bassuk and Brad A. Amendt, University of Iowa; Edward B. Li and Eric C. Liao, Massachusetts General Hospital; Trevor J. Williams, University of Colorado Denver at Anschutz Medical Campus; Yang Chai, University of Southern California; and Simon Gregory and Allison Ashley-Koch, Duke University Medical Center.

Pedbot video game

Pedbot’s next step – Home-based therapy

Pedbot video game

Pedbot’s home version adapts the same airplane-themed video game to a smaller therapeutic platform that is more affordable to build.

The novel ankle rehabilitation robot built at Children’s National to help children with cerebral palsy build ankle strength and control through video gaming is taking a big step forward. Engineers have created a smaller, more affordable version of the robotic platform using 3D printed parts, to explore the effectiveness of a home-based therapy program.

“We’re seeing preliminary success in our trial for in clinic use of the Pedbot. Now we’re hoping to see if making the technology accessible at home means that 1) Kids use it more often and 2) More frequent, regular use over time leads to better range of motion,” says Kevin Cleary, Ph.D., the Sheikh Zayed Institute for Pediatric Surgical Innovation’s bioengineering technical director and engineering lead for Pedbot.

Pedbot’s video game, designed by software engineer Hadi Fooladi, M.S., allows kids to pilot an airplane through a series of hoops at varying speeds as determined by the therapist and programmer. The game isn’t the only thing that’s unique about this therapeutic robot, however.

Just like the clinic version, the home model moves in three translational directions (x, y and z) and rotates about three axes (the x, y and z axes), similar to the movement of a flight simulator. The result is a robot that helps the patient exercise across a greater range of motion and build muscle strength in a way that more closely mimics real-life ankle function.

Pedbot Home potentially eliminates an additional major therapeutic barrier – the clinic appointment.

“The great thing about Pedbot is you’re constantly working to reach a moving target, and the therapist can vary the movement type as much or as little as needed for each patient,” says Catherine Coley, DPT, a physical therapist at Children’s National who is a member of the Pedbot development team. “We think the home version might make it easier for the child to succeed with a long term therapy program by removing the need for repeat clinic visits.”

“What if a child could come home from school and do their therapy at home after dinner? Would doing it every day for 20 minutes benefit the child more than just coming to see us once or twice a week for an hour? Can we make it easier for our patients to cooperate and follow through with therapy homework? These are some of the questions that we hope we can answer during our trial for the home version,” says Sally Evans, M.D., division chief of Pediatric Rehabilitation Medicine at Children’s National and clinical lead for the project.

The cross-functional Pedbot team includes engineers Reza Monfaredi Ph.D. and Tyler Salvador, B.S., as well as additional physical therapists, Stacey Kovelman, P.T. and Justine Belchner, P.T., and Sara Alyamani, B.A. Future expansions will include the addition of electromyography measurements in collaboration with Paola Pergami, M.D., Ph.D. and incorporation of other patient populations with Beth Wells, M.D.

Pedbot Home is currently being piloted in the home setting, with the goal of enrolling additional families to participate in a trial within the next year. The work is supported by a $500,000 federal grant from the Department of Health and Human Services’ National Institute on Disability, Independent Living, and Rehabilitation Research.

E coli bacteria

Urinary bacteria in spinal cord injury cases may tip balance toward UTIs

E coli bacteria

Patients with spinal cord injuries nearly universally have bacteria present in their urine regardless of whether they have a urinary tract infection.

The fallout from spinal cord injury doesn’t end with loss of mobility: Patients can have a range of other issues resulting from this complex problem, including loss of bladder control that can lead to urine retention. One of the most serious implications is urinary tract infections (UTIs), the most common cause of repeat hospitalization in people with spinal cord injuries, explains Hans G. Pohl, M.D., associate chief in the division of Urology at Children’s National Health System.

Diagnosing UTIs in people with spinal cord injuries is trickier than in people who are otherwise healthy, Dr. Pohl explains. Patients with spinal cord injuries nearly universally have bacteria present in their urine regardless of whether they have a UTI. It’s unclear whether these bacteria are innocent bystanders or precursors to UTIs in patients who don’t yet show symptoms. And although antibiotics can wipe out this bacterial population, these drugs can have undesirable side effects and frequent use can promote development of antibiotic-resistant bacteria.

Although clinical dogma has long promoted the idea that “healthy” urine is sterile, Dr. Pohl and colleagues have shown that a variety of bacteria live in urine, even in people without symptoms. These microorganisms, like the intestinal microbiome, live in harmony with their hosts and may even help promote health. However, it’s unclear what this urinary microbiome might look like for patients with spinal cord injury before, during and after UTIs.

To start investigating this question, Dr. Pohl and co-authors recently reported a case study they published online Sept. 21, 2018, in Spinal Cord Series and Cases. The case report about a 55-year-old man who had injured the thoracic segment of his spinal cord—about the level of the bottom of his shoulder blades—in a skiing accident when he was 19 was selected as “Editor’s Choice” for the journal’s October 2018 issue.  The patient had a neurogenic bladder, which doesn’t function normally due to impaired communication with the spinal cord. To compensate for this loss of function, this patient needed to have urine removed every four to six hours by catheterization.

Over eight months Dr. Pohl, the study’s senior author, and colleagues collected 12 urine samples from this patient:

  • One was collected at a time the patient didn’t show any symptoms of a UTI
  • Nine were collected when the patient had UTI symptoms, such as bladder spasticity
  • Two samples were collected when the patient had finished antibiotic treatment for the UTI.

The researchers split each sample in half. One part was put through a standard urinalysis and culture, much like what patients with a suspected UTI would receive at the doctor’s office. The other part was analyzed using a technique that searched for genetic material to identify bacteria that might be present and to estimate their abundance.

The researchers found a variety of different bacteria present in these urine samples. Regardless of the patient’s health status and symptoms, the majority of these bacterial species are known to be pathogenic or potentially pathogenic. By contrast, this patient’s urine microbiome appeared to largely lack bacterial species known to be either neutral or with potentially probiotic properties, such as Lactobacillus.

All of the bacteria that grew in culture also were identified by their genetic material in the samples. However, genetic sequencing also identified a possible novel uropathogenic species called Burkholderia fungorum that didn’t grow in the lab in five of the samples. This bacterium is ubiquitous in the environment and has been identified in soil- and plant-based samples. It also has been discovered in the respiratory secretions of patients with cystic fibrosis, in patients with a heart condition called infectious endocarditis, in the vaginal microbiota of patients with bacterial vaginosis, and in the gut of patients with HIV who have low T-cell counts. Dr. Pohl says it’s unclear whether this species played an infectious role in this patient’s UTI or whether it’s just part of his normal urine flora.

“Consistent with our previous work, this case report demonstrates that rather than healthy urine being sterile, there is a diverse urine bacterial ecosystem during various states of health and disease,” Dr. Pohl says. “Rather than UTIs resulting from the growth or overgrowth of a single organism, it’s more likely that a change in the healthy balance of the urine ecosystem might cause these infections.”

By monitoring the relative abundance of different bacteria types present in the urine of patients with spinal cord injury and combining this information with a patient’s symptoms, Dr. Pohl says doctors may be able to make more accurate UTI diagnoses in this unique population.

In addition to Dr. Pohl, study co-authors include Marcos Pérez-Losada, Ljubica Caldovic, Ph.D., Bruce Sprague and Michael H. Hsieh, M.D., Children’s National; Emma Nally, Suzanne L. Groah and Inger Ljungberg, MedStar National Rehabilitation Hospital; and Neel J. Chandel, Montefiore Medical Center.

AlgometRX

Breakthrough device objectively measures pain type, intensity and drug effects

AlgometRX

Clinical Research Assistant Kevin Jackson uses AlgometRx Platform Technology on Sarah Taylor’s eyes to measure her degree of pain. Children’s National is testing an experimental device that aims to measure pain according to how pupils react to certain stimuli. (AP Photo/Manuel Balce Ceneta)

Pediatric anesthesiologist Julia C. Finkel, M.D., of Children’s National Health System, gazed into the eyes of a newborn patient determined to find a better way to measure the effectiveness of pain treatment on one so tiny and unable to verbalize. Then she realized the answer was staring back at her.

Armed with the knowledge that pain and analgesic drugs produce an involuntary response from the pupil, Dr. Finkel developed AlgometRx, a first-of-its-kind handheld device that measures a patient’s pupillary response and, using proprietary algorithms, provides a diagnostic measurement of pain intensity, pain type and, after treatment is administered, monitors efficacy. Her initial goal was to improve the care of premature infants. She now has a device that can be used with children of any age and adults.

“Pain is very complex and it is currently the only vital sign that is not objectively measured,” says Dr. Finkel, who has more than 25 years of experience as a pain specialist. “The systematic problem we are facing today is that healthcare providers prescribe pain medicine based on subjective self-reporting, which can often be inaccurate, rather than based on an objective measure of pain type and intensity.” To illustrate her point, Dr. Finkel continues, “A clinician would never prescribe blood pressure medicine without first taking a patient’s blood pressure.”

The current standard of care for measuring pain is the 0-to-10 pain scale, which is based on subjective, observational and self-reporting techniques. Patients indicate their level of pain, with zero being no pain and ten being highest or most severe pain. This subjective system increases the likelihood of inaccuracy, with the problem being most acute with pediatric and non-verbal patients. Moreover, Dr. Finkel points out that subjective pain scores cannot be standardized, heightening the potential for misdiagnosis, over-treatment or under-treatment.

Dr. Finkel, who serves as director of Research and Development for Pain Medicine at the Sheikh Zayed Institute for Pediatric Surgical Innovation at Children’s National, says that a key step in addressing the opioid crisis is providing physicians with objective, real-time data on a patient’s pain level and type, to safely prescribe the right drug and dosage or an alternate treatment.,

She notes that opioids are prescribed for patients who report high pain scores and are sometimes prescribed in cases where they are not appropriate. Dr. Finkel points to the example of sciatica, a neuropathic pain sensation felt in the lower back, legs and buttocks. Sciatica pain is carried by touch fibers that do not have opioid receptors, which makes opioids an inappropriate choice for treating that type of pain.

A pain biomarker could rapidly advance both clinical practice and pain research, Dr. Finkel adds. For clinicians, the power to identify the type and magnitude of a patient’s nociception (detection of pain stimuli) would provide a much-needed scientific foundation for approaching pain treatment. Nociception could be monitored through the course of treatment so that dosing is targeted and personalized to ensure patients receive adequate pain relief while reducing side effects.

“A validated measure to show whether or not an opioid is indicated for a given patient could ease the health care system’s transition from overreliance on opioids to a more comprehensive and less harmful approach to pain management,” says Dr. Finkel.

She also notes that objective pain measurement can provide much needed help in validating complementary approaches to pain management, such as acupuncture, physical therapy, virtual reality and other non-pharmacological interventions.

Dr. Finkel’s technology, called AlgometRx, has been selected by the U.S. Food and Drug Administration (FDA) to participate in its “Innovation Challenge: Devices to Prevent and Treat Opioid Use Disorder.” She is also the recipient of Small Business Innovation Research (SBIR) grant from the National Institute on Drug Abuse.

DNA moleucle

PAC1R mutation may be linked to severity of social deficits in autism

DNA moleucle

A mutation of the gene PAC1R may be linked to the severity of social deficits experienced by kids with autism spectrum disorder (ASD), finds a study from a multi-institutional research team led by Children’s National faculty. If the pilot findings are corroborated in larger, multi-center studies, the research published online Dec. 17, 2018, in Autism Research represents the first step toward identifying a potential novel biomarker to guide interventions and better predict outcomes for children with autism.

As many as 1 in 40 children are affected by ASD. Symptoms of the disorder – such as not making eye contact, not responding to one’s name when called, an inability to follow a conversation of more than one speaker or incessantly repeating certain words or phrases – usually crop up by the time a child turns 3.

The developmental disorder is believed to be linked, in part, to disrupted circuitry within the amygdala, a brain structure integral for processing social-emotional information. This study reveals that PAC1R is expressed during key periods of brain development when the amygdala – an almond-shaped cluster of neurons – develops and matures. A properly functioning amygdala, along with brain structures like the prefrontal cortex and cerebellum, are crucial to neurotypical social-emotional processing.

“Our study suggests that an individual with autism who is carrying a mutation in PAC1R may have a greater chance of more severe social problems and disrupted functional brain connectivity with the amygdala,” says Joshua G. Corbin, Ph.D., interim director of the Center for Neuroscience Research at Children’s National Health System and the study’s co-senior author. “Our study is one important step along the pathway to developing new biomarkers for autism spectrum disorder and, hopefully, predicting patients’ outcomes.”

The research team’s insights came through investigating multiple lines of evidence:

  • They looked at gene expression in the brains of an experimental model at days 13.5 and 18.5 of fetal development and day 7 of life, dates that correspond with early, mid and late amygdala development. They confirmed that Pac1r is expressed in the experimental model at a critical time frame for brain development that coincides with the timing for altered brain trajectories with ASD.
  • They looked at gene expression in the human brain by mining publicly available genome-wide transcriptome data, plotting median PAC1R expression values for key brain regions. They found high levels of PAC1R expression at multiple ages with higher PAC1R expression in male brains during the fetal period and higher PAC1R expression in female brains during childhood and early adulthood.
  • One hundred twenty-nine patients with ASD aged 6 to 14 were recruited for behavioral assessment. Of the 48 patients who also participated in neuroimaging, 20 were able to stay awake for five minutes without too much movement as the resting state functional magnetic resonance images were captured. Children who were carriers of the high-risk genotype had higher resting-state connectivity between the amygdala and right posterior temporal gyrus. Connectivity alterations in a region of the brain involved in processing visual motion may influence how kids with ASD perceive socially meaningful information, the authors write.
  • Each child also submitted a saliva sample for DNA genotyping. Previously published research finds that a G to C single nucleotide polymorphism, a single swap in the nucleotides that make up DNA, in PAC1R is associated with higher risk for post traumatic stress disorder in girls. In this behavioral assessment, the research team found children with autism who carried the homozygous CC genotype had higher scores as measured through a validated tool, meaning they had greater social deficits than kids with the heterozygous genotype.

All told, the project is the fruit of six years of painstaking research and data collection, say the researchers. That includes banking patients’ saliva samples collected during clinical visits for future retrospective analyses to determine which genetic mutations were correlated with behavioral and functional brain deficits, Corbin adds.

“Lauren Kenworthy, who directs our Center for Autism Spectrum Disorders, and I have been talking over the years about how we could bring our programs together. We homed in on this project to look at about a dozen genes to assess correlations and brought in experts from genetics and genomics at Children’s National to sequence genes of interest,” he adds. “Linking the bench to bedside is especially difficult in neuroscience. It takes a huge amount of effort and dozens of discussions, and it’s very rare. It’s an exemplar of what we strive for.”

In addition to Corbin, study co-authors include Lead Author Meredith Goodrich and Maria Jesus Herrero, post-doctoral fellow, Children’s Center for Neuroscience Research; Anna Chelsea Armour and co-Senior Author Lauren Kenworthy, Ph.D., Children’s Center for Autism Spectrum Disorders; Karuna Panchapakesan, Joseph Devaney and Susan Knoblach, Ph.D., Children’s Center for Genetic Medicine Research; Xiaozhen You and Chandan J. Vaidya, Georgetown University; and Catherine A.W. Sullivan and Abha R. Gupta, Yale School of Medicine.

Financial support for the research described in this report was provided by DC-IDDRC under awards HD040677-07 and 1U54HD090257, the Clinical and Translational Science Institute at Children’s National, The Isidore and Bertha Gudelsky Family Foundation and the National Institutes of Health under awards MH083053-01A2 and MH084961.

Kwitkin-family-photo

A rare diet: Could you survive on six grams of protein a day?

Clara Barton

Clara Rose Kwitkin was born at a healthy 7 pounds, 14 ounces on Nov. 12, 2018.

 

Children’s National Health System introduces clinic to help adults with phenylketonuria, a rare inherited disorder, experiment with Palynziq, an FDA-approved drug that helps the body process phenylalanine.

“What can you eat?” is a common question for picky eaters, particularly individuals with phenylketonuria (PKU), a rare inherited metabolic condition that prevents an enzyme in the body from processing the amino acid phenylalanine (Phe), a building block of protein.

About one in 10,000 or 15,000 people in the U.S. with PKU, approximately 50,000 people worldwide, understand this line of questioning. 

“It’s emotional,” says 27-year-old Ashley Kwitkin, a Northern Va. resident and new mom, about the complexities of following a low-Phe diet.

When Kwitkin previously went “off diet,” meaning eating more than six grams of protein a day, the equivalent of a handful of almonds, she felt the consequences: irritability, moodiness and poor concentration. Her body couldn’t process Phe.

The National Institutes of Health mentions excessive levels of Phe can lead to toxic levels in the blood and tissues, and even cause brain damage.

Kwitkin’s motivation during pregnancy quickly changed. “It’s not just me anymore,” notes Kwitkin, who gave birth to Clara Rose Kwitkin on Nov. 12. “It’s me and my child. The moment we met her, our lives changed forever.”  

If Kwitkin went off her PKU-approved diet while pregnant, she may have increased the chance that her baby would have been born with intellectual disabilities, heart problems, delayed growth, microcephaly or behavioral problems.

Fortunately, Kwitkin received medical clearance from her doctors to move forward with a safe and healthy pregnancy. While she is a carrier for PKU, her husband is not – which meant their child had less than a 1 percent change of being born with this rare disease.

Like many adults with PKU, Kwitkin is grateful for advancements with early disease detection and treatment. If she had been born six decades earlier, she may have been hospitalized for neurological impairments, before PKU was recognized, screened for and treated with a low-Phe diet to support cognitive development.

Kwitkin is grateful for the popularity of gluten-free, PKU-friendly products and specialty food stores – compared to when she was growing up and had to order medical bread, which cost $13 a loaf and came out of a can. This trend makes it easy to find PKU-friendly meals to eat.

Expanding her palate is one of the reasons Kwitkin is following the results of a new clinic at Children’s National to help people with PKU experiment with Palynziq, an enzyme substitution therapy that helps people with PKU digest Phe.

Palynziq was approved by the Food and Drug administration on May 24, 2018 and a team of metabolic dietitians and geneticists at Children’s National have been helping a handful of adult PKU patients test out the treatment, slowly, over a preliminary period.

To prescribe the drug in a medically-supervised setting, the doctors introduced the injectable enzyme treatment to participants in small .25-mg doses, which started on Aug. 20, 2018, and monitored their progress as they worked up to the standard 20-mg treatment, a milestone many in the group reached in November 2018.

If the treatment continues to go well, based on the results of the FDA’s recommended titration schedule, the medical team will enroll additional participants in its clinic and share the results with other medical centers.

The timing of the new Palynziq clinic is also perfect for Kwitkin. If the drug works for her in the future, she won’t have to make three dinners: one for her, one for her husband and one for Clara Rose. While Kwitkin is currently off the low-Phe diet, she looks forward to resuming a PKU-friendly diet in the future – especially as she and her husband consider having a second child.

Kwitkin’s PKU-friendly diet consists of “safe” foods, such as unlimited amounts of peaches, apples, cabbage and green beans, which contain zero traces of Phe, and portioned amounts of low-Phe foods: pasta, bread, baked potatoes and specialty-ordered, low-protein items.

While planning for pregnancy, Kwitkin adjusted her protein intake to eight grams of protein a day. During pregnancy, she ate up to 19 grams of daily protein – to satiate her body’s needs and the needs of her baby – and regularly checked in with Erin MacLeod, Ph.D., a metabolic dietitian at Children’s National who is guiding the Palynziq clinic.

Kwitkin-family-photo

Ashley Kwitkin and her husband look forward to expanding their family in the future.

While the new Palynziq therapy carries potential benefits, such as the ability to join a family potluck without counting grams of protein, have second servings of broccoli, a carefully-portioned vegetable on the PKU diet, or thinking clearly while eating a low-Phe diet, a motivating factor for many of MacLeod’s patients, the treatment also carries risks. 

Potential side effects of Palynziq include severe allergic reactions – swelling of the face, lips, eyes and tongue – as well as shortness of breath, a faster heart rate, rashes, confusion, lightheadedness, nausea and vomiting.

So far, minor side effects, such as rashes and injection-site soreness, are noted among participants in the Palynziq trial at Children’s National. The full 20-mg prescription could be increased or decreased, based on how a person’s immune system responds to the foreign agent. If all continues to go well for the participants, they will take the recommended dose, equivalent to about 20 injections a week, and check in with the medical team every three months during the first year. Based on their benefit-risk assessment of the new drug, they can then segue into bi-annual visits if they want to continue with the treatment.  

“Our goal is to help participants decide if this therapy is a good fit for them, based on their lifestyle and health preferences,” notes MacLeod. For some people, MacLeod explains, such as those entering college or who form strong social connections around food, and who may experience the impact of going ‘off diet,’ this treatment could change their lives. Others, such as those who are in the process of moving to a new city or are in a busy period of their lives, may prefer following a strict low-protein diet compared to taking daily enzyme injections.

Another factor Kwitkin and MacLeod will keep in mind as the Palynziq clinics advance is the treatment’s variability. For example, Kuvan, the first drug of its kind is an enzyme therapy developed to help the body break down Phe. The drug was approved by the FDA in 2007, but only works in a small portion of the PKU population – about 10 percent of patients with a mild form of the condition. Instead of eating high-Phe foods, Kuvan users follow a mild-protein diet.

MacLeod views this type of individualized meal planning and how her patients react to food as a science, which drew her to the field. She works with 70 to 100 PKU patients each year from infancy to adulthood, including patients in their 60s, to help them meet their unique metabolic needs.

MacLeod is also tracking the use of gene therapy in metabolic disorders in addition to how the gut flora, or gut bacteria, helps PKU patients modulate and break down Phe.

“A lot of research is happening right now,” adds MacLeod about accelerations with PKU therapy. “I’ve seen how patients respond to new treatments, including a carefully-measured, low-Phe diet, and how their lives start to change once they can think clearly and feel better, which is a motivating factor and goal for many of our patients. I’ve also seen others pursue their dreams, which in Kwitkin’s case was to become a parent and history teacher.”

Like Kwitkin and others impacted by PKU, MacLeod looks forward to ongoing developments and research for this rare disease.

 

Andrew Dauber at his computer doing a Reddit AMA

Thirteen questions for a pediatric endocrinologist

Andrew Dauber at his computer doing a Reddit AMA

Andrew Dauber, M.D., hosts an AMA chat with Reddit’s science community and offers feedback about height, growth disorders and pediatric endocrinology.

Andrew Dauber, M.D., MMSc., the division chief of endocrinology at Children’s National, spoke about epigenetics – how genes are expressed – and about all things related to pediatric endocrinology in a recent Ask Me Anything (AMA) chat with Reddit’s science community.

We’ve selected highlights from several questions Dr. Dauber received. You can view the full AMA discussion on Reddit.

Q1: What will the future of type 1 diabetes treatment look like?

As a pediatric endocrinologist, Dr. Dauber sees a lot of patients with type 1 diabetes. He predicts technology will pave the way for advancements with continuous glucose monitoring and encourage a ‘real-time’ interaction between patients and providers:

“I anticipate that within a few years, everyone will have access to continuous glucose monitoring technology and that these will be seamlessly connected to insulin pumps or artificial pancreas technologies,” types Dr. Dauber in response to the first AMA question. “I also think there will be more virtual interaction between medical providers and patients with doctors and nurses reviewing blood sugar data in the cloud.”

Q2: What height range is considered normal for a growing child? What is the difference between short stature and a height problem?

The Centers for Disease Control and Prevention has a growth chart, which shows ‘normal’ ranges, based on statistical definitions of height in the general population.

“The truth is that I know plenty of people who have heights below the ‘normal’ population, and they don’t think they have a problem at all,” says Dr. Dauber. “From a genetics point of view, the question can be reframed: When do we call a genetic variant a ‘mutation’ versus a rare variant in the population? For example: If there is a genetic change that 1 in a 1,000 people have that causes you to be 2 inches shorter – is that a problem? Is that a disease?”

“From a clinical perspective, I tend to have a discussion with my patients and their families and ask them how their stature is affecting their lives and whether changing that would really make a meaningful difference,” adds Dr. Dauber. “I believe that this is a very personal decision but people need to be realistic about expected outcomes.”

Q3: What are your favorite case studies about atypical growth or height patterns?

Dr. Dauber references two case studies about growth and puberty:

The growth case study refers to the PAPPA2 gene, which was particularly meaningful for Dr. Dauber since he got to know the family and was able to provide answers to a previously undiagnosed medical mystery about short stature. This research is also opening future studies and analysis about the regulation of IGF-1 bioavailability.

The puberty case study looks at the opposite end of growth and development: precocious puberty. In this case an inherited MKRN3 gene mutation resulted in new insight about the regulation of pubertal timing: Deficiency of MKRN3 caused central precocious puberty in humans. Girls who had inherited the mutated genes from their father (an imprint gene) started to develop breasts before age 6. The results were published in The New England Journal of Medicine.

Q4: What are the differences with consistent and inconsistent growth disorders? Could one arm or leg experience accelerated or stunted growth?

“Most genetic disorders that affect growth will have a uniform effect throughout the body as they are likely to affect all aspects of the skeleton,” says Dr. Dauber. “That being said, there are some notable exceptions such as Russell-Silver syndrome which presents with body asymmetry. There are also somatic mutations (mutations which are just present in some cells in the body) that can lead to segmental areas of overgrowth leading to asymmetry.”

Q5: Can you predict height and growth by looking at genetic factors? What are your thoughts about polygenic risk scores?

“Polygenic risk scores will probably play more of a role in the future to help determine risk of a certain disease,” says Dr. Dauber. “Right now, for most conditions, the risk score does not explain a substantial enough fraction of the variation to help with prediction.”

Dr. Dauber discusses how this works for height, a highly hereditable trait, in The Journal for Clinical Endocrinology and Metabolism. In the review, Dr. Dauber and the study co-authors note that individuals with extreme heights are more likely to have abnormal stature as a result of a severe mutation that causes a growth disorder. For these individuals, whole exome sequencing may reveal gene mutations.

However, the study authors note that for now, the role of these technologies in individuals with extreme stature but without any syndromic features has not been rigorously and systematically explored. (Dr. Dauber and a team of endocrinologists from leading children’s hospitals are currently using electronic health records to study and track these types of genetic clues over time.)

Q6: The general public is excited about genetics and ongoing research, especially with consumer applications – such as genetic tests, including 23andMe. What misconceptions about genetics do people have? What ethical concerns do geneticists share right now?

“Many people think that genetics is completely deterministic,” says Dr. Dauber. “In reality, most genetic variants influence a person’s predisposition toward a trait or disease but don’t actually determine the outcome. Also, the genetic sequence itself is just the first step. Epigenetics, gene regulation, and gene-environment interactions are all important and we are just scratching the surface of understanding these areas.”

“I think that people engaged in genetics research are very interested in the ethical questions,” adds Dr. Dauber. “The problem is that technology is advancing at such a rapid pace, that often consumers are using technologies in ways that we haven’t yet had time to figure out the ethics for. The medical community is often playing catch up.”

Q7: Aside from using gene modifications to cure diseases, where or when should we draw the line in terms of enhancement?

“I think genetic modification for enhancement is a very dangerous slippery slope that we should avoid,” says Dr. Dauber. “We really don’t know the full effect of many genes and by enhancing them, we could be causing lots of problems that we can’t anticipate. There is a reason that evolution is a slow process that happens over millions of years. I think we need to start with the most devastating diseases and try to cure those first.”

Q8: Would it be ethical to use CRISPR on the genes for short stature to produce tall offspring if the risks are sufficiently small? This would be similar to what Dr. He did, but without the ethical violations.

“This is a fascinating question and it will become more of an issue over time,” says Dr. Dauber. “Where do we draw the line between fixing, preventing disease and enhancing physical function? Personally, I think using genome editing to promote height is a terrible idea. Our current perception that taller height is more desirable is a social construct and varies by culture. This idea also changes over time.”

Q9: Overall, how does this fit into meeting unmet medical needs?

“I would be very wary about trying to design our children’s physical features,” Dr. Dauber notes. “We need to figure out as a society what diseases are sufficiently problematic that we feel comfortable trying to eliminate them via genome editing.”

Q10: How many genes control acromegaly? Is it possible (in theory) to Top of Formselect them just to gain the positive effects of gigantism without the health risks?

Dr. Dauber explains that acromegaly, a condition often referred to as gigantism, is caused by a growth hormone-producing tumor. There are a few genes known to cause these tumors, including the AIP, and there was recently a genetic cause of X-linked gigantism, which was published in The New England Journal of Medicine.

“This basic idea is a good one,” notes Dr. Dauber. “We can find genes that when mutated can cause tall stature – and then try to manipulate those pathways. A great example is the NPR2 gene, which when mutated can cause short or tall stature. This pathway is being targeted for therapeutics related to achondroplasia.”

The National Institutes of Health (NIH) refers to achondroplasia as ‘short-limbed dwarfism,’ which results in an average-sized trunk with short limbs, especially arms and legs, due to a lack of cartilage turning into bone. The average height of an adult male with achondroplasia is 4 feet, 4 inches, while the average height of adult females with achondroplasia is less than 4 feet, 1 inch. In this case, manipulating growth pathways may help alleviate health problems associated with achondroplasia: lack of mobility or range of motion, an enlarged head, apnea, ear infections and spinal stenosis, or a compression or pinching of the spinal cord.

Q11: Give us a history lesson. Why are there variations of height within populations, such as Asia and Latin America?

“The average height in a population is due to the influence of literally thousands of common genetic variants,” says Dr. Dauber. “These population differences have evolved over thousands of years due to a combination of migration and selection. There is a well-known difference in the genetic makeup of various populations which likely underlies the differences across the globe. There are even differences within Europe.”

Q12: Are there examples of pseudoscience or theories about growth, such as recommendations to eat a certain food instead of taking growth hormones to correct for a growth disorder, which runs contrary to scientific evidence, that drive you crazy?

“I don’t really get bothered by crazy theories, but it is upsetting when patients and their families get swindled into spending their money on therapies that aren’t truly effective,” says Dr. Dauber. “People ask me all the time if a certain food or exercise can make their child taller. The bottom line is that in a well-nourished (and healthy) child, there is no magical food that is going to make them tall.”

Q13: According to almost every theory of how life evolved on Earth, from religion to evolution, we all have one common ancestor. In theory doesn’t that make us all cousins?

“Yes, just very distant ones,” says Dr. Dauber. “People always point out the vast number of differences between races but in fact we are all more than 99.9 percent identical on a genetic level.”

Stay on top of the latest pediatric endocrinology news by following @EndoDocDauber and @ChildrensHealth on Twitter: #GrowUpStronger.

Groundbreaking at Research and Innovation Campus

Children’s National breaks ground on research and innovation hub

Groundbreaking at Research and Innovation Campus

Pictured, from left to right: Mike Williams, board chair of Children’s National, Mark Batshaw, M.D., chief academic officer and physician-in-chief at Children’s National, Kurt Newman, M.D., president and CEO of Children’s National, Ward 4 Councilman Brandon Todd, Norvell Coots, M.D., president and CEO of Holy Cross Health, and Sarosh Olpadwala, director of real estate, Office of the Deputy Mayor for Planning and Economic Development.

On November 28, 2018, Children’s National Health System marked the official start of construction on its pediatric research and innovation campus with a groundbreaking event. The campus will be distinct nationally as a freestanding research and innovation complex focused on pediatric medicine.

“We had this vision to create a one-of-a-kind pediatric and research innovation campus, which is also a first for Washington, D.C.,” said Kurt Newman, M.D., president and CEO of Children’s National. “If we’re going to help children grow up stronger, then it’s not enough to just provide excellent medical care. We have to work on the research and innovation, which drives discoveries and improves the care for our next generation.”

Children’s National is renovating four existing buildings on a nearly 12-acre portion of the former Walter Reed Army Medical Center campus. This includes a research and innovation building, an outpatient care center, which will include comprehensive primary care services for the community and a conference theatre.

With 160,000 sq. ft. of research and innovation space – and room for expansion – Children’s National will be able to expand its efforts in the high-impact opportunities in pediatric genomic and precision medicine. Developing treatments that can target an individual’s disease more precisely can produce better outcomes with fewer side effects. This focus on personalized research will also improve access at the main hospital by freeing up space for the high-demand critical care services that Children’s National provides.

These efforts will be anchored by three areas of strength at Children’s National: the Center for Genetic Medicine Research, headed by Eric Vilain, M.D., Ph.D., the clinical molecular genetics laboratory directed by Meghan Delaney, DO, MPH, and the Rare Disease Institute headed by Marshall Summar, M.D.

A critical component of the new campus’ success is its proximity to key partners, such as industry, universities, academic medical centers, federal agencies and start-up companies. By working together with these partners, Children’s National hopes to create an ecosystem for nurturing innovation from laboratory discovery all the way through to commercialization.

The new pediatric research and innovation center will also provide an economic benefit of $150 million through its completion date of 2020, providing 350 temporary jobs and 110 permanent positions. The long-term growth, based on an independent study by McKinsey and Company, is exponential and could produce up to $6.2 billion in economic benefit by 2030, based on projected tax revenue and 2,100 permanent jobs, pending future research partnerships.

“Medical advances that effectively treat or prevent disease mean that our children will live fuller, more productive lives,” said Mike Williams, board chair of Children’s National. “That is real economic and societal benefit.”

little girl in hosptial corridor

A growing list of factors that impact CKD severity for kids

little girl in hosptial corridor

Myriad biological and societal factors can impact the occurrence and accelerate progression of chronic kidney disease for children of African descent – including preterm birth, exposure to toxins during gestation and lower socioeconomic status – and can complicate these children’s access to effective treatments.

Myriad biological and societal factors can impact the occurrence and accelerate progression of chronic kidney disease (CKD) for children of African descent – including preterm birth, exposure to toxins during gestation and lower socioeconomic status – and can complicate these children’s access to effective treatments, according to an invited commentary published in the November 2018 edition of American Journal of Kidney Diseases.

Clinicians caring for “these vulnerable children should be mindful of these multiple competing and compounding issues as treatment options are being considered along the continuum from CKD to kidney failure to transplantation,” writes Marva Moxey-Mims, M.D., chief of the Division of Nephrology at Children’s National Health System.

The supplemental article was informed by lessons learned from The Chronic Kidney Disease in Children (CKiD) longitudinal study and conversations that occurred during the Frank M. Norfleet Forum for Advancement of Health, “African Americans and Kidney Disease in the 21st Century.”

African American children represent 23 percent of the overall population of kids with CKD in the CKiD study. While acquired kidney diseases can get their start during childhood when the diseases betray few symptoms, the full impact of illness may not be felt until adulthood. A number of factors can uniquely affect children of African descent, heightening risk for some kids who already are predisposed to suffering more severe symptoms. These include:

  • Preterm birth. African American children make up 36 percent of patients in CKiD with glomerular disease, which tends to have faster progression to end-stage renal disease. These diseases impair kidney function by weakening glomeruli, which impairs the kidneys’ ability to clean blood. Patients with a high-risk apolipoprotein L1 (APOL1) genotype already are at higher risk for focal segmental glomerulosclerosis (FSGS) and CKD. Researchers hypothesize that preterm birth may represent “a second hit that facilitates the development of glomerular damage resulting from the high-risk genotype.” According to the Centers for Disease Control and Prevention, 1 in 10 U.S. infants in 2016 was born preterm, e.g., prior to 37 weeks gestation.
  • APOL1 genotype. Compared with children who had a low-risk genotype and FSGS, children with a high-risk genotype had higher rates of uncontrolled hypertension, left ventricular hypertrophy, elevated C-reactive protein levels and obesity.
  • Human immunodeficiency viral (HIV) status. About 65 percent of U.S. children with HIV-1/AIDS are African American. In a recent nested case-control study of children infected with HIV in the womb, infants with high-risk APOL1 genotypes were 3.5 times more likely to develop CKD with viral infection serving as “a likely second hit.”
  • Access to kidney transplant. African American adults experience a faster transition to end-stage renal disease and are less likely to receive kidney transplants. African American children with CKD from nonglomerular diseases begin renal replacement therapy 1.6 years earlier than children of other races, after adjusting for socioeconomic status. Their wait for dialysis therapy was 37.5 percent shorter. However, these African American children waited 53.7 percent longer for transplants. Although donor blood types, genetic characteristics and other biological factors each play contributing roles, “these findings may reflect sociocultural and institutional differences not captured by socioeconomic status,” Dr. Moxey-Mims writes.

To alleviate future health care disparities, she suggests that additional research explore the impact of expanding services to pregnant women to lower their chances of giving birth prematurely; early childhood interventions to help boost children’s educational outcomes, future job prospects and income levels; expanded studies about the impact of environmental toxicities on prenatal and postnatal development; and heightened surveillance of preterm infants as they grow older to spot signs of kidney disease earlier to slow or prevent disease progression.

“Clinicians can now begin to take into account genetics, socioeconomic status and the impact of the built environment, rather than blaming people and assuming that their behavior alone brought on kidney disease,” Dr. Moxey-Mims adds. “Smoking, not eating properly and not exercising can certainly make people vulnerable to disease. However, there are so many factors that go into developing a disease that patients cannot control: You don’t control to whom you’re born, where you live or available resources where you live. These research projects will be useful to help us really get to the bottom of which factors we can impact and which things can’t we prevent but can strive to mitigate.”

The article covered in this post is part of a supplement that arose from the Frank M. Norfleet Forum for Advancement of Health: African Americans and Kidney Disease in the 21st Century, held March 24, 2017, in Memphis, Tennessee. The Forum and the publication of this supplement were funded by the Frank M. Norfleet Forum for Advancement of Health, the Community Foundation of Greater Memphis and the University of Tennessee Health Science Center.

Test tube that says IGF-1 test

PAPPA2: A genetic mystery

Test tube that says IGF-1 test

What would happen if you suddenly stopped growing at age 12 or 13?

Solving genetic growth mysteries and scheduling regular appointments with pediatric endocrinologists is atypical for most parents and pediatricians.

However, for children with growth disorders – a classification that typically describes children below the third or above the 97th percentile of growth charts for their age – receiving a diagnosis is half the battle to reaching average height. Understanding and creating treatment for a growth disorder, which could stem from an underlying medical illness, a genetic mutation or a problem with endocrine function, such as the production or action of growth hormone, is often the next step.

For Andrew Dauber, M.D., MMSc., the chief of endocrinology at Children’s National Health System, a third step is to use these clues to create larger datasets and blueprints to identify risk factors for rare growth disorders. By understanding genetic markers of growth disorders, endocrinologists can identify solutions and create plans for multidisciplinary care to help children reach developmental milestones and receive coordinated care throughout their lifespan.

A case study that Dauber and his research team continue to explore is how to correct for mutations in the PAPPA2 gene, which regulates human growth by releasing a key growth factor called insulin-like growth factor 1 (IGF-1). Dauber and his colleagues recently described a mutation in PAPPA2, observed in two families with multiple children affected with significant short stature. He found that this mutation decreased the bioavailability of IGF-1, stunting the growth and development of the children who carry this mutation.

While the PAPPA2 mutation is rare, endocrinologists, like Dauber, who understand its function and dysregulation can create solutions to support IGF-1 bioavailability, thereby supporting healthy growth and development in children.

Understanding barriers to IGF-1 function can also help researchers gain insight into the relationship between PAPPA2, levels of circulating insulin in the body, which could cause insulin resistance, and other growth hormones. For now, Dauber and his research team are exploring how to use PAPPA2 to increase IGF-1 in circulation among people with height disorders in the hopes of improving their growth.

“The population of children who have PAPPA2 mutations is small and we’re finding out that two children could respond to the same treatment in different ways,” says Dauber. “One medication could work modestly in one child and support short growth spurts, such as growing by 5 or 6 cm a year. It could also create undesirable side effects, such as headaches and migraines in another, and render it ineffective. However, the clues we walk away with enable us to test new solutions, and confirm or dissolve our hunches, about what may be preventing the bioactive release of essential growth hormones.”

To generate controls for healthy patterns of growth and development, Dauber and his research team are analyzing the relationship between PAPPA2, STC2 and IGFBP-3 concentrations among 838 relatively healthy pediatric participants, ages 3-18, with traditional growth patterns.

They are studying PAPPA2, STC2 and intact IGFBP-3 concentrations throughout childhood and the researchers are already surprised to find PAPPA2, a positive modulator of growth and IGF- bioavailability, decreased with age, while STC2, a negative modulator and traditional growth inhibitor, increased with age.

“As pediatric endocrinology researchers and clinicians, we’re looking at the pathology of traditional growth patterns and growth disorders with an open mind,” says Dr. Dauber. “These data sets are invaluable as they confirm or challenge our theories, which enable us to create and test new forms of personalized treatments. We’ll continue to share this knowledge, which informs other researchers and accelerates the field of pediatric endocrinology.”

This research was presented at the annual meeting of the European Society of Pediatric Endocrinology in Athens on Sept. 28, 2018.

Dauber and his research team will present their findings at endocrinology conferences and grand rounds throughout 2018 and 2019.

To view Dr. Dauber’s most recent research and pediatric endocrinology reviews, visit PubMed.

Andrew Dauber

Growth disorder study starts by analyzing DNA

The National Institutes of Health has awarded Andrew Dauber, M.D., MMSc, the chief of endocrinology at Children’s National Health System, a five-year grant that will allow four pediatric health systems to compile and study clinical and genetic markers of severe pediatric growth disorders.

The study will use the electronic health records of large health systems combined with DNA samples from dozens of children, with the goal of enabling endocrinologists to detect children with previously undiagnosed severe genetic growth disorders.

“If you’re a pediatrician treating an 8-year-old patient who has stopped growing, the first thing you’ll want to do is determine the underlying cause, which could be due to many factors including a genetic mutation,” says Dr. Dauber. “There are many reasons why children grow poorly and it is often very difficult to figure out what is causing the problem. However, the various causes may be treated quite differently and may alert us to other medical issues that we need to watch out for. We need to be able to identify clues from the patient’s clinical presentation that may point us to the right diagnosis.”

Dr. Dauber and endocrinology researchers from Children’s National Health System, Cincinnati Children’s Hospital Medical Center, Boston Children’s Hospital and The Children’s Hospital of Philadelphia will use electronic health records to identify children who likely have rare genetic growth disorders. They will then use cutting-edge DNA sequencing technologies, whole exome sequences, to identify novel genetic causes of severe growth disorders. Patients with growth hormone resistance, resistance to insulin-like growth factor 1 (IGF-I) and severe short stature inherited from a single parent will be recruited for the initial phases of the study.

“It’s rare to find patients meeting criteria for each of these subgroups, which is why it’s critical to work collaboratively across institutions,” says Dr. Dauber. “This type of genetic sorting and sharing brings us closer to identifying new markers for severe or treatment-resistant growth disorders, which will help alert pediatricians and parents to potential risks earlier on in a child’s life.”

In addition to assessing genetic markers for short stature, the endocrinologists will conduct pilot studies of targeted interventions, such as IGF-I therapy in patients with mutations in the growth hormone pathway, based on these genetic underpinnings.

“Ideally, by identifying markers of severe growth disorders first, we’ll be able to provide targeted treatments and therapies later on to help patients throughout their lifespan,” adds Dr. Dauber.

Typical treatments for atypical growth patterns include growth hormone or less commonly insulin-like growth factor, or IGF-1, for short stature and hormone-inhibiting treatments for precocious puberty.

The multicenter clinical trial is funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), under grant Ro1HD093622, and runs through June 30, 2023.