Rare Disorders Archives

Gene therapy offers potential long-term treatment for limb-girdle muscular dystrophy 2B

January 4, 2022

Microscopic visual of a diseased muscle section. Credit: Daniel Bittel.

Children’s National Hospital experts developed a new pre-clinical gene therapy for a rare disorder, known as limb-girdle muscular dystrophy (LGMD) 2B, that addresses the primary cellular deficit associated with this disease. Using a single injection of a low dose gene therapy vector, researchers restored the ability of injured muscle fibers to repair in a way that reduced muscle degeneration and enhanced the functioning of the diseased muscle. The treatment was safe, attenuated fibro-fatty muscle degeneration, and restored myofiber size and muscle strength, according to the study published in the Journal of Clinical Investigation.

With an incidence of less than 1 in 100,000, LGMD2B is a rare disorder caused by a genetic mutation in a large gene called dysferlin. This faulty gene leads to muscle weakness in the arms, legs, shoulder and pelvic girdle. Affected children and adults face trouble walking, climbing stairs and getting out of chairs. Individuals typically lose the ability to walk within years after the onset of symptoms, and often need assistance with everyday tasks such as showering, dressing and transferring.

This study described a new approach that avoids the need for packaging a large gene, like dysferlin, or giving a large vector dose to target the muscles, which are bottlenecks faced in ongoing gene therapy efforts aimed at muscular dystrophies.

“Currently, patients with LGMD2B have no gene or drug-based therapies available to them, and we are amongst the few centers developing therapeutic approaches for this disease,” said Jyoti K. Jaiswal, M.Sc. Ph.D., senior investigator of the Center for Genetic Medicine Research at Children’s National. “We are working to further enhance the efficacy of this approach and perform a longer-term safety and efficacy study to enable the clinical translation of this therapy.”

The genetic defect in dysferlin that is associated with LGMD2B causes the encoded protein to be truncated or degraded. This hinders the muscle fiber’s ability to heal, which is required for healthy muscles. In recessive genetic disorders, like LGMD2B, common pre-clinical gene therapy approaches usually target the mutated gene in the muscle, making them capable of producing the missing proteins.

“The large size of the gene mutated in this disease, and impediments in body-wide delivery of gene therapy vectors to reach all the muscles, pose significant challenges for developing gene therapies to treat this disease,” said Jaiswal.

To overcome these challenges, the researchers found another way to slow down the disease’s progression. The authors built upon their previous discovery that acid sphingomyelinase (hASM) protein is required to repair injured muscle cells. In this current work, the research team administered a single in vivo dose of an Adeno-associated virus (AAV) vector that produces a secreted version of hASM in the liver, which then was delivered to the muscles via blood circulation at a level determined to be efficacious in repairing LGMD2B patient’s injured muscle cells.

“Increased muscle degeneration necessitates greater muscle regeneration, and we found that improved repair of dysferlin-deficient myofibers by hASM-AAV reduces the need for regeneration, causing a 2-fold decrease in the number of regenerated myofibers,” said Daniel Bittel, D.P.T., PhD., research postdoctoral fellow of the Center for Genetic Medicine Research at Children’s National and a lead author of this study.

Sreetama Sen Chandra, Ph.D., who was a research postdoctoral fellow at Children’s National at the time of this study and served as co-lead author, also added that “these findings are also of interest to patients with Niemann-Pick disease type A since the pre-clinical model for this disease also manifests poor sarcolemma repair.”

Children’s National researchers of the Center for Genetic Medicine Research and the Rare Disease Institute (RDI) are constantly pursuing high-impact opportunities in pediatric genomic and precision medicine. Both centers combine its strengths with public and private partners, including industry, universities, federal agencies, start-up companies and academic medical centers. They also serve as an international referral site for rare disorders.

Gene therapy Schematic. Credit: Daniel Bittel.

Using genomics to solve a 20-year case study

April 29, 2019

“The advent of different technologies and techniques over the years allowed pieces of her diagnosis to be made – and then brought all together,” says Andrew Dauber, M.D., MMSc.

After 20 years, a patient’s family received an answer to a decades-long genetic mystery. Their daughter had two rare disorders, Angelman syndrome and P450scc deficiency, which was detected after researchers found out she had uniparental disomy, two copies of chromosome 15 from one parent and none from another.

The research paper, entitled “Adrenal Insufficiency, Sex Reversal and Angelman Syndrome due to Uniparental Disomy Unmasking a Mutation in CYP11A1,” was published on March 22, 2018, and recognized as the best novel insight paper published by Hormone Research in Paediatrics in 2018, announced at the Pediatric Endocrine Society’s Annual Meeting in Baltimore on Saturday, April 27, 2019.

By using a variety of genetic tools, including whole-exome sequencing, microarray analyses and in-vitro modeling for gene splicing, the researchers were able to confirm this patient had uniparental disomy, a recessive genetic condition. They learned that after she received two impaired copies of chromosome 15 from her father, this woman developed a hormonal problem that led to adrenal insufficiency and sex reversal. This explained why she physically presented as a female, despite having testes and a Y-chromosome. It also explained other symptoms, including developmental delays and seizures.

“It’s a unique conglomeration of symptoms, manifested by the combination of these two very rare disorders,” says Andrew Dauber, M.D., MMSc., the division chief of endocrinology at Children’s National Health System and a guiding research author of this study. “The advent of different technologies and techniques over the years allowed pieces of her diagnosis to be made – and then brought together, commencing a 20-year diagnostic odyssey.”

For example, each of the conditions this patient has is known and rare: Angelman syndrome affects about one in 10 to 20,000 people in the U.S. Typical symptoms include those observed in this patient: delayed development, intellectual disability, speech impairment and seizures. Side-chain cleavage disorder, which leads to adrenal disorders and sex reversal, is also very rare. In 2005 the chances of survival with a P450scc defect were slim, but since then more than 28 infants have been diagnosed with this gene deficiency, which is required to convert cholesterol to pregnenolone, a hormone in the adrenal gland.

Dr. Dauber notes the chances of this occurring again are highly unlikely. The odds here are one in a gazillion. In this case, one disorder unmasked another, leaving researchers with new insights into the methodology for unraveling ultra-rare genetic disorders or for more common rare conditions.

“Knowing about the gene that caused the adrenal insufficiency and understanding this etiology won’t change medical care for this patient, but it will change the way researchers think about genetic detective work and about combining different technologies,” says Dr. Dauber. “We know that genetic disorders can be complex presentations of different disorders combined. This patient didn’t have one disorder, but three.”

When asked about the significance of the award, Dr. Dauber notes that, “It’s not that other people haven’t recognized this concept before, but this case is a striking example of it. Different technologies will unveil different types of genetic changes, which is why you have to use the right technology or the right technologies in the right combination to piece together the whole picture.”

Ahlee Kim, M.D., the lead study author and a clinical research fellow at Cincinnati Children’s Hospital Medical Center, will receive the award and the honorarium.

Additional study authors include Masanobu Fujimoto, Ph.D., Vivian Hwa, Ph.D., and Philippe Backeljauw, M.D., from Cincinnati Children’s Hospital.

The research was supported by grant K23HD07335, awarded to Dr. Dauber, from the Eunice Kennedy Shriver National Institute of Child Health and Human Development of the National Institutes of Health (NIH). Additional funding included grant 1UL1TR001425 from the NIH’s National Center for Advancing Translational Sciences.

Rare Disease Institute director named to Global Commission to End the Diagnostic Odyssey for Children

March 21, 2018

Marshall Summar, M.D., director of the Children’s National Rare Disease Institute (CNRDI), has been named to the Global Commission to End the Diagnostic Odyssey for Children.

Children’s National Health System has announced that Marshall Summar, M.D., director of the Children’s National Rare Disease Institute (CNRDI), has been named to the Global Commission to End the Diagnostic Odyssey for Children (“the Global Commission”), an alliance dedicated to shortening the multi-year journey that rare disease patients and families endure on the road to diagnosis.

Established in partnership with Shire, Microsoft and EURORDIS, the Global Commission is comprised of a multi-disciplinary team of global experts that have the commitment, creativity and technological expertise required to make a substantial difference in the lives of the millions of children living with a rare disorder.

“Providing more help to children born with rare genetic diseases continues to be one of the core challenges of 21^st century medicine,” says Dr. Summar, who notes that patients typically visit up to eight doctors and often receive two or three misdiagnoses along the way. “Even upon diagnosis, patients are hindered by scarce treatment options and approximately a third of patients die before their fifth birthday. We are committed to changing this trend at the CNRDI and are excited to have the opportunity to share our expertise with this alliance on a global stage.”

The Global Commission is focused on developing an actionable roadmap for the field of rare disease that offers recommendations to address core challenges that prevent timely diagnosis for rare disease patients, including improving physicians’ ability to identify and diagnose rare disorders, empowering patients to take an active role in their healthcare and providing high-level policy guidance to help rare disease patients achieve better health outcomes.

Beginning its work in 2018, the Global Commission expects to publish a roadmap that encapsulates the collective findings in early 2019. Over the course of the next year, the alliance will gather input from patients, families and other experts to gain key insights and develop solutions to shorten the diagnostic odyssey.

In the United States, it is estimated that one in 10 people has a rare disease – approximately 80 percent of which are genetically based. Additionally, the National Institutes of Health reports that more than 80 percent are childhood diseases and more than 25 percent of children admitted to pediatric hospitals have a rare disease.

Horizon Pharma gifts $3M to establish Horizon Pharma Clinical Care Endowment at Children’s National Rare Disease Institute

March 2, 2018

“Patients and families with rare conditions deserve to be treated in a place with the medical knowledge to provide quick, clear answers and the expert care they need,” says Marshall Summar, M.D., director of the CNRDI.

Children’s National Health System and Horizon Pharma plc are pleased to announce the creation of the Horizon Pharma Clinical Care Endowment, the first clinical team endowment at the Children’s National Rare Disease Institute (CNRDI). The endowment is made possible by a generous six-year, $3 million commitment from Horizon Pharma USA, Inc., a wholly owned subsidiary of Horizon Pharma plc –a biopharmaceutical company dedicated to improving the lives of people living with rare diseases.

“Patients and families with rare conditions deserve to be treated in a place with the medical knowledge to provide quick, clear answers and the expert care they need,” says Marshall Summar, M.D. , director of the CNRDI. “We are grateful for Horizon and their support of our mission to make the Children’s National Rare Disease Institute that place. This endowment will support a dedicated team that can provide optimal, comprehensive care to more patients and ensure that families have a trusted source for all aspects of their health care.”

The Horizon Pharma Clinical Care Endowment will generate revenue annually, providing stable support for an expert care team at the CNRDI. Each team will be comprised of a clinical geneticist and support team members – such as genetic counselors, nutritionists and social workers – all specializing in the care of children with rare disease.

The long-term support provided by the Horizon Pharma Clinical Care Endowment will give the CNRDI a firm foundation for treating patients earlier, more consistently and over the course of their lifetime. Horizon’s commitment marks the first donor-funded endowment at the CNRDI.

Currently, it is estimated that one in 10 Americans has a rare disease – approximately 80 percent of which are genetically based. Additionally, the NIH reports that more than 80 percent are childhood diseases, and more than 25 percent of children admitted to pediatric hospitals have a rare disease.

The CNRDI is a first-of-its-kind center focused exclusively on advancing the care and treatment of children and adults with rare genetic diseases. It is the first National Organization for Rare Disorders (NORD) Center of Excellence and aims to provide a medical home for patients and families seeking the most advanced care and expertise for rare genetic conditions that remain largely unknown to the general medical community.

Newborn screening leader selected to advisory committee on heritable disorders in newborns and children

January 11, 2018

Sarah Viall

Sarah Viall, PPCNP, coordinator for the Newborn Screening Program at the Children’s National Rare Disease Institute (CNRDI), has been invited to serve on the Education and Training Workgroup of the Health Resources & Services Administration’s (HRSA) Advisory Committee on Heritable Disorders in Newborns and Children (ACHDNC).

Established under the Public Health Service Act, the ACHDNC focuses on reducing morbidity and mortality in newborns and children who have, or are at risk for, genetic disorders. The Committee currently recommends that all newborn screening programs include a Uniform Screening Panel that monitors for a total of 34 core disorders and another 26 secondary disorders.

In addition to developing recommendations on national newborn screening guidelines, the ACHDNC also advises the U.S. Department of Health and Human Services Secretary on the most appropriate application of newborn screening technologies, tests, policies and standards. The Committee provides technical information that helps develop Heritable Disorders Program policies and priorities that enhance the ability of local and state health agencies to provide screening, healthcare services and counseling for newborns and children affected by genetic disease.

Viall had previously spent a year observing meetings for the ACHDNC Education and Training Workgroup.

“I am thrilled to be an official member that can contribute to the important work of educating communities about newborn screening,” says Viall.

$3M Retrophin gift establishes Rare Disease Network at Children’s National

January 10, 2018

“This is an exciting first step toward a new era of rare disease care and innovation,” says Marshall Summar, M.D., director of the CNRDI. “We are grateful for this gift from Retrophin that will help us accelerate progress for our patients and families and pursue work that will have a far-reaching impact on both children and adults across the country and around the world thanks to the support of Retrophin.”

Children’s National Health System and Retrophin, Inc. have announced the creation of the Retrophin Rare Disease Network at Children’s National. Retrophin, a biopharmaceutical company specializing in identifying, developing and delivering life-changing therapies to people living with rare diseases, has committed $3 million over the next six years to support the work of the Children’s National Rare Disease Institute (CNRDI). Retrophin’s commitment marks the first corporate gift to CNRDI.

“One of the chief challenges of 21st century pediatric medicine is our continued inability to provide more help to those born with rare genetic diseases,” says Marshall Summar, M.D., director of the CNRDI. “This is an exciting first step toward a new era of rare disease care and innovation. We are grateful for this gift from Retrophin that will help us accelerate progress for our patients and families and pursue work that will have a far-reaching impact on both children and adults across the country and around the world thanks to the support of Retrophin.”

As a dedicated source of funding, the Retrophin Rare Disease Network will advance the CNRDI’s efforts to create a global “hub and spoke” model for disseminating and streamlining patient access to optimal care methods and among national and international peer institutions. The network will enhance the field of rare disease medicine by standardizing care models and establishing world-wide best practices in diagnosis and treatment.

The Retrophin Rare Disease Network will also provide funding for new dedicated positions at the CNRDI and build on the Institute’s existing digital and telemedicine programs, to extend the reach of its researchers and caregivers in areas where there is currently limited care available for children and adults living with rare diseases.

CNRDI is a first-of-its-kind center focused exclusively on advancing the care and treatment of children and adults with rare genetic diseases. The first National Organization for Rare Disorders (NORD) Center of Excellence, it aims to provide a medical home for patients and families seeking the most advanced care and expertise for rare genetic conditions that remain largely unknown to the general medical community.

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