Tag Archive for: PAPPA2

Andrew Dauber

Andrew Dauber, M.D., MMSc, caps off research success with award and reception

Andrew Dauber

Unfortunately, we’ve been notified that the ENDO2020 conference has been canceled due to concerns of COVID-19. Because of this, we will not be hosting our reception in honor of Andrew Dauber, M.D., on Sunday, March 29.

We hope to see you at a future Endocrinology or Pediatric Endocrinology event.

Children’s National Hospital is incredibly proud of the work Dr. Dauber has done in the endocrinology community.

Andrew Dauber, M.D., MMSc, division chief of Endocrinology at Children’s National Hospital, will be awarded the 2020 Richard E. Weitzman Outstanding Early Career Investigator Award at ENDO 2020. The prestigious award will be presented at the annual meeting of the Endocrine Society in recognition of Dauber’s work in understanding the regulation of growth and puberty, and applying innovative genetic technologies to studying pediatric endocrinology. Dauber credits many collaborators throughout the world, as well as the team at Children’s National for the award.

With a five-year grant from the National Institutes of Health (NIH), Dauber and colleagues from the Cincinnati Children’s Hospital Medical Center, Boston Children’s Hospital and the Children’s Hospital of Philadelphia are using electronic health records to identify children who likely have rare genetic growth disorders. Using cutting-edge DNA sequencing technologies, including whole exome sequencing, the researchers are aiming to identify novel genetic causes of severe growth disorders. The first paper describing genetic findings in patients with high IGF-1 levels was published in Hormone Research in Paediatrics in December 2019.

Dauber and researchers at Cincinnati Children’s Hospital Medical Center are exploring how to treat patients with mutations in the PAPPA2 gene. In 2016, the group described the first patients with mutations in this gene who had decreased the bioavailability of IGF-1, stunting their growth and development. In their current phase of research, findings are emphasizing the importance of this gene in regulating IGF-1 bioavailability throughout childhood. The ultimate aim is to create therapies to increase IGF-1 bioavailability, thereby supporting healthy growth and development in children. Their first study to track PAPPA2 and intact IBGBP-3 concentrations throughout childhood was published in the European Journal of Endocrinology in January 2020.

Dauber is particularly interested in studying children with dominantly inherited forms of short stature. Along with collaborators in Cincinnati, he currently has an ongoing treatment trial using growth hormone in patients with Aggrecan gene mutations.  Dauber hopes to announce soon a new clinical trial for children with all forms of dominantly inherited short stature.

Study upon study has shown us that there are many factors that affect an individual’s height and growth. As these studies and the conversation around how to identify and address genomic anomalies become more prevalent, the team at Children’s National is increasingly interested in engaging with other centers around the country. In the coming months, the Children’s National Research & Innovation Campus will open on the grounds of the former Walter Reed Army Medical Center, which will serve as a one-of-a-kind pediatric research and innovation hub. A critical component to this campus is the co-location of Children’s National research with key partners and incubator space.

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.