Tag Archive for: international

Andrea Gropman

$5M in federal funding to help patients with urea cycle disorders

Andrea Gropman

Andrea L. Gropman, M.D.: We have collected many years of longitudinal clinical data, but with this new funding now we can answer questions about these diseases that are meaningful on a day-to-day basis for patients with urea cycle disorders.

An international research consortium co-led by Andrea L. Gropman, M.D., at Children’s National Hospital has received $5 million in federal funding as part of an overall effort to better understand rare diseases and accelerate potential treatments to patients.

Urea cycle disorder, one such rare disease, is a hiccup in a series of biochemical reactions that transform nitrogen into a non-toxic compound, urea. The six enzymes and two carrier/transport molecules that accomplish this essential task reside primarily in the liver and, to a lesser degree, in other organs.

The majority of patients have the recessive form of the disorder, meaning it has skipped a generation. These kids inherit one copy of an abnormal gene from each parent, while the parents themselves were not affected, says Dr. Gropman, chief of the Division of Neurodevelopmental Pediatrics and Neurogenetics at Children’s National. Another more common version of the disease is carried on the X chromosome and affects boys more seriously that girls, given that boys have only one X chromosome.

Regardless of the type of urea cycle disorder, when the urea cycle breaks down, nitrogen converts into toxic ammonia that builds up in the body (hyperammonemia), particularly in the brain. As a result, the person may feel lethargic; if the ammonia in the bloodstream reaches the brain in high concentrations, the person can experience seizures, behavior changes and lapse into a coma.

Improvements in clinical care and the advent of effective medicines have transformed this once deadly disease into a more manageable chronic ailment.

“It’s gratifying that patients diagnosed with urea cycle disorder now are surviving, growing up, becoming young adults and starting families themselves. Twenty to 30 years ago, this never would have seemed conceivable,” Dr. Gropman says. “We have collected many years of longitudinal clinical data, but with this new funding now we can answer questions about these diseases that are meaningful on a day-to-day basis for patients with urea cycle disorders.”

In early October 2019, the National Institutes of Health (NIH) awarded the Urea Cycle Disorders Consortium for which Dr. Gropman is co-principal investigator a five-year grant. This is the fourth time that the international Consortium of physicians, scientists, neuropsychologists, nurses, genetic counselors and researchers has received NIH funding to study this group of conditions.

Dr. Gropman says the current urea cycle research program builds on a sturdy foundation built by previous principal investigators Mendel Tuchman, M.D., and Mark Batshaw, M.D., also funded by the NIH. While previous rounds of NIH funding powered research about patients’ long-term survival prospects and cognitive dysfunction, this next phase of research will explore patients’ long-term health.

Among the topics they will study:

Long-term organ damage. Magnetic resonance elastrography (MRE) is a state-of-the-art imaging technique that combines the sharp images from MRI with a visual map that shows body tissue stiffness. The research team will use MRE to look for early changes in the liver – before patients show any symptoms – that could be associated with long-term health impacts. Their aim is spot the earliest signs of potential liver dysfunction in order to intervene before the patient develops liver fibrosis.

Academic achievement. The research team will examine gaps in academic achievement for patients who appear to be underperforming to determine what is triggering the discrepancy between their potential and actual scholastics. If they uncover issues such as learning difficulties or mental health concerns like anxiety, there are opportunities to intervene to boost academic achievement.

“And if we find many of the patients meet the criteria for depression or anxiety disorders, there are potential opportunities to intervene.  It’s tricky: We need to balance their existing medications with any new ones to ensure that we don’t increase their hyperammonemia risk,” Dr. Gropman explains.

Neurologic complications. The researchers will tap continuous, bedside electroencephalogram, which measures the brain’s electrical activity, to detect silent seizures and otherwise undetectable changes in the brain in an effort to stave off epilepsy, a brain disorder that causes seizures.

“This is really the first time we will examine babies’ brains,” she adds. “Our previous imaging studies looked at kids and adults who were 6 years and older. Now, we’re lowering that age range down to infants. By tracking such images over time, the field has described the trajectory of what normal brain development should look like. We can use that as a background and comparison point.”

In the future, newborns may be screened for urea cycle disorder shortly after birth. Because it is not possible to diagnose it in the womb in cases where there is no family history, the team aims to better counsel families contemplating pregnancy about their possible risks.

Research described in this post was underwritten by the NIH through its Rare Diseases Clinical Research Network.

Beth Tarini

Getting to know SPR’s future President, Beth Tarini, M.D., MS

Beth Tarini

Quick. Name four pillar pediatric organizations on the vanguard of advancing pediatric research.

Most researchers and clinicians can rattle off the names of the Academic Pediatric Association, the American Academy of Pediatrics and the American Pediatric Society. But that fourth one, the Society for Pediatric Research (SPR), is a little trickier. While many know SPR, a lot of research-clinicians simply do not.

Over the next few years, Beth A. Tarini, M.D., MS, will make it her personal mission to ensure that more pediatric researchers get to know SPR and are so excited about the organization that they become active members. In May 2019 Dr. Tarini becomes Vice President of the society that aims to stitch together an international network of interdisciplinary researchers to improve kids’ health. Four-year SPR leadership terms begin with Vice President before transitioning to President-Elect, President and Past-President, each for one year.

Dr. Tarini says she looks forward to working with other SPR leaders to find ways to build more productive, collaborative professional networks among faculty, especially emerging junior faculty. “Facilitating ways to network for research and professional reasons across pediatric research is vital – albeit easier said than done. I have been told I’m a connector, so I hope to leverage that skill in this new role,” says Dr. Tarini, associate director for Children’s Center for Translational Research.

“I’m delighted that Dr. Tarini was elected to this leadership position, and I am impressed by her vision of improving SPR’s outreach efforts,” says Mark Batshaw, M.D., Executive Vice President, Chief Academic Officer and Physician-in-Chief at Children’s National. “Her goal of engaging potential members in networking through a variety of ways – face-to-face as well as leveraging digital platforms like Twitter, Facebook and LinkedIn – and her focus on engaging junior faculty will help strengthen SPR membership in the near term and long term.”

Dr. Tarini adds: “Success to me would be leaving after four years with more faculty – especially junior faculty – approaching membership in SPR with the knowledge and enthusiasm that they bring to membership in other pediatric societies.”

SPR requires that its members not simply conduct research, but move the needle in their chosen discipline. In her research, Dr. Tarini has focused on ensuring that population-based newborn screening programs function efficiently and effectively with fewer hiccups at any place along the process.

Thanks to a heel stick to draw blood, an oxygen measurement, and a hearing test, U.S. babies are screened for select inherited health conditions, expediting treatment for infants and reducing the chances they’ll experience long-term health consequences.

“The complexity of this program that is able to test nearly all 4 million babies in the U.S. each year is nothing short of astounding. You have to know the child is born – anywhere in the state – and then between 24 and 48 hours of birth you have to do testing onsite, obtain a specific type of blood sample, send the blood sample to an off-site lab quickly, test the sample, find the child if the test is out of range, get the child evaluated and tested for the condition, then send them for treatment. Given the time pressures as well as the coordination of numerous people and organizations, the fact that this happens routinely is amazing. And like any complex process, there is always room for improvement,” she says.

Dr. Tarini’s research efforts have focused on those process improvements.

As just one example, the Advisory Committee on Heritable Disorders in Newborns and Children, a federal advisory committee on which she serves, was discussing how to eliminate delays in specimen processing to provide speedier results to families. One possible solution floated was to open labs all seven days, rather than just five days a week. Dr. Tarini advocated for partnering with health care engineers who could help model ways to make the specimen transport process more efficient, just like airlines and mail delivery services. A more efficient and effective solution was to match the specimen pick-up and delivery times more closely with the lab’s operational times – which maximizes lab resources and shortens wait times for parents.

Conceptual modeling comes so easily for her that she often leaps out of her seat mid-sentence, underscoring a point by jotting thoughts on a white board, doing it so often that her pens have run dry.

“It’s like a bus schedule: You want to find a bus that not only takes you to your destination but gets you there on time,” she says.

Dr. Tarini’s current observational study looks for opportunities to improve how parents in Minnesota and Iowa are given out-of-range newborn screening test results – especially false positives – and how that experience might shake their confidence in their child’s health as well as heighten their own stress level.

“After a false positive test result, are there parents who walk away from newborn screening with lingering stress about their child’s health? Can we predict who those parents might be and help them?” she asks.

Among the challenges is the newborn screening occurs so quickly after delivery that some emotionally and physically exhausted parents may not remember it was done. Then they get a call from the state with ominous results. Another challenge is standardizing communication approaches across dozens of birthing centers and hospitals.

“We know parents are concerned after receiving a false positive result, and some worry their infant remains vulnerable,” she says. “Can we change how we communicate – not just what we say, but how we say it – to alleviate those concerns?”

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.”