Tag Archive for: genetic medicine

Youn Hee Jee

Shaping the future of pediatric endocrinology

Youn Hee Jee

“Select patients will have the opportunity to participate in research studies focused on cutting-edge genomic investigations into their growth disorders,” says Youn Hee Jee, M.D., M.Med., endocrinologist.

“We’re dedicated to unraveling the mysteries that families have long sought answers to,” says Andrew Dauber, M.M.Sc., M.D., chief of Endocrinology at Children’s National Hospital. “There are numerous endocrine and genetic conditions with the potential to impact a child’s growth. That’s why we’ve assembled a team of leading endocrinologists and geneticists to create a new Growth Specialty Clinic and address these issues with a fresh perspective.”

This team, combined with the expertise of the hospital’s translational scientists, is making significant progress in identifying the causes of a variety of growth disorders and developing innovative treatments. And at the core of this work, Dr. Dauber says, is a recognition of the unique impact endocrine disorders have on each individual child.

What’s unique

Leveraging the expertise of Medical Geneticists Natasha Shur, M.D., and Deepika Burkardt, D.O., from the Children’s National Rare Disease Institute – the largest clinical genetics program in the United States – the growth clinic taps into substantial knowledge in the genetics of growth.

Dr. Shur emphasizes the commitment to providing answers for these families. “This collaborative effort goes beyond diagnosis; it opens doors to potential treatment options.”

The Growth Specialty Clinic is for children with severe undiagnosed growth disorders that are suspected to have a genetic etiology and children with rare genetic diagnoses who would benefit from the expertise of practitioners more familiar with those disorders. It is also closely linked to the Center for Genetic Medicine Research.

“Select patients will have the opportunity to participate in research studies focused on cutting-edge genomic investigations into their growth disorders,” says Youn Hee Jee, M.D., M.Med., endocrinologist.

In one case, Dr. Jee identified a new genetic cause of an overgrowth syndrome. Rare genetic conditions known as generalized overgrowth syndromes manifest as excessive body growth during fetal life and/or childhood, frequently resulting in tall stature. She is investigating the mechanisms that promote healthy bone growth.

Additionally, Dr. Jee identified a new genetic cause of short stature. Her research showed that the identified genetic cause impairs the recycling of essential proteins for growth, expanding our knowledge of human growth.

Moving the field forward

“We’re taking innovative approaches to treatment by leveraging our insights into the genetic origin of each patient’s growth disorder,” says Dr. Dauber.

In the brief time since the clinic’s launch, several new diagnoses and treatment pathways have already been offered. In one single-patient study, researchers were able to successfully overcome the patient’s growth hormone resistance using a targeted approach, and the patient has shown significant catch-up growth after one year of treatment.

Children’s National is also at the forefront of other groundbreaking research, launching novel clinical trials that are advancing the field of endocrinology:

  • Vosoritide clinical trial: Children’s National has the first clinical trial in the world testing Vosoritide in children with certain genetic causes of short stature. Researchers have enrolled approximately 50 subjects with exciting preliminary results for patients with Noonan syndrome, Aggrecan gene mutations and NPR2 gene mutations. All 24 hypochondroplasia patients have completed the 18-month trial. Dr. Dauber intends to present results at the 2024 American College of Medical Genetics meeting in Toronto.
  • Hypochondroplasia study: Children’s National is the first site to launch BioMarin’s new natural history study for children with hypochondroplasia which will also be a lead into their future Phase 3 trial.

Read more about our advances in Diabetes & Endocrinology.

Eric Vilain explores “Disorders/differences of sex development: A world of uncertainty”

Eric Vilain

In his keynote address at Children’s National’s Research and Education Week, Eric Vilain, M.D., Ph.D., explored the genetics of sex development and sex differences.

After announcing he would be joining Children’s National as the new director of the Center for Genetic Medicine Research late last year, internationally-renowned geneticist Eric Vilain, M.D., Ph.D., gave a keynote address entitled “Disorders/Differences of Sex Development: A World of Uncertainty” during Children’s National’s Research and Education Week.

Dr. Vilain explored the genetics of sex development and sex differences – specifically differences of sex development (DSD), congenital conditions in which the development of chromosomal, gonadal or anatomical sex is atypical.

“The first step in sex development is looking at genetic sex and how it results in gonadal sex,” Dr. Vilain said. “From a scientific perspective, we are trying to take a step back and assess how cells become more typically male or female.”

He explained that, at conception, the fundamental difference between male and female embryos exists in the sex chromosome complement. Both XX and XY embryos have bipotential gonads capable of differentiating into a testis or an ovary, though embryos are virtually indistinguishable from a gender perspective up until six weeks in utero.

Eric Vilain - sex differences

According to Dr. Vilain, the fundamental difference between male and female embryos exists in the sex chromosome complement, though embryos are virtually indistinguishable until six weeks in utero.

Whether or not a bipotential gonad forms is largely left up to the genetic makeup of the individual. For example, a gene in the Y chromosome (SRY) triggers a cascade of genes that lead to testis development. If there is no Y chromosome, it triggers a series of pro-female genes that lead to ovarian development.

However, genetic mutations can alter the subsequent steps of sex differentiation. Dr. Vilain explained that, depending on the genotype, an individual may experience normal gonadal development, but abnormal development of the genitalia.

He also noted that these genes are critical to determining the differences between men and women in non-gonadal tissues as well.

In addition to exploring the genetics of sex development and sex differences, Dr. Vilain’s research explores the biological bases of sex variations in predisposition to disease. His clinic at Children’s National is completely devoted to caring for patients with a wide array of genetic and endocrine issues, particularly cases dealing with variations of sex development.

For seven years, Children’s National’s Research and Education Week has celebrated the excellence in research, education, innovation and scholarship at Children’s National and around the world. This year, the annual event focused how “Collaboration Leads to Innovation” and celebrated the development of ideas that aim to transform pediatric care.