About Schaaf-Yang Syndrome

What is Schaaf-Yang syndrome?


Schaaf-Yang syndrome (SYS) is a genetic disorder caused by a disruption of the MAGEL2 gene on chromosome 15. The disrupted gene causing Schaaf-Yang syndrome is also missing in another, more common genetic disorder, Prader-Willi syndrome (PWS). PWS is caused when MAGEL2 and several additional genes on chromosome 15 are missing or inactivated.

The ultimate goal of the MAGEL2 work supported by FPWR is to develop new therapies that will improve the lives of individuals with SYS and PWS.

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What are the symptoms of Schaaf-Yang syndrome?

Schaaf-Yang syndrome shares many clinical features with Prader-Willi syndrome. Those include hypotonia, feeding difficulties during infancy, global developmental delay/intellectual disability, and sleep apnea. However, patients with Schaaf-Yang syndrome have a relatively higher prevalence of autism spectrum disorder, and almost all of them manifest joint contractures, typically affecting the finger joints, but in more severe cases also involving knees and elbows.

Publication Documents the Similarities and Differences Between PWS and SYS

Emma was the 28th patient diagnosed with Schaaf-Yang syndrome. Dr. Christian Schaaf and his group, in collaboration with Dr. Jennifer Miller, have published the results of an FPWR funded study examining the clinical similarities and differences between Prader-Willi syndrome (PWS) and Schaaf-Yang syndrome (SYS). Highlights from the paper are discussed in our blog: Study Compares Schaaf-Yang and Prader-Willi Syndromes.

The full publication Hormonal, metabolic and skeletal phenotype of Schaaf-Yang syndrome: a comparison to Prader-Willi syndrome (published March 2018) can be found here.

A second publication in 2020 describes the adult phenotype of Schaaf-Yang syndrome. Click here to read the publication: The Adult Phenotype of Schaaf-Yang syndrome. In this publication, the researchers show that the adult phenotype of Schaaf-Yang syndrome is more closely related to the adult phenotype of Prader-Willi syndrome than previously thought.

Recorded Informational Presentation

In August 2017, FPWR hosted the first Schaaf-Yang Family Conference. In the recording below, Drs. Schaaf, Potts and Wevrick describe the symptoms, common features, and what we know about the Magel2 gene. A must watch for any parent with a child diagnosed with SYS!





Download the What is SYS? Fact Sheet

How is Schaaf-Yang Syndrome diagnosed?

A suspected diagnosis of Schaaf-Yang Syndrome may be confirmed through whole exome sequencing or through MAGEL2 sequencing. MAGEL2 mutations can be de novo, meaning the mutation is a new event and not inherited, or can be inherited through the father.

Have you recently received a diagnosis of Schaaf-Yang syndrome? Download First Steps: A Parent's Guide to SYS. This guide was written for parents, by parents and contains important information to help guide you through the beginning of this journey!

Download First Steps for SYS


Is there a cure for Schaaf-Yang syndrome?

Currently, there is no cure for Schaaf-Yang syndrome. The Foundation for Prader-Willi Research is interested in advancing research toward understanding and treating specific aspects of the syndrome, with the goal of an eventual cure.

Where can I learn more about Schaaf-Yang Syndrome?

Watch our presentations from the 2020 Schaaf-Yang Syndrome Family Conference featuring presentations by Dr. Ryan Potts, Dr. Rachel Wevrick, and Dr. Christian Schaaf. Learn more about the SYS research landscape, next steps in SYS research, and the clinical aspects of SYS in these conference presentations. Watch the videos >>


Another way to learn more is through this great GeneReviews on Schaaf-Yang Syndrome! This is a really comprehensive overview of the clinical characteristics of Schaaf-Yang, and is meant to provide information to medical professionals. Please click here to access this free PDF, and feel free to share with your doctor!

Peer-Reviewed Publications



Get Involved

Our foundation relies on volunteers, like you, to help us accelerate our programs. We welcome you to join our team and get involved as we work together to eliminate the challenges of Schaaf-Yang and Prader-Willi syndromes.

Anyone can fundraise for SYS research - parents, grandparents, brothers and sisters, aunts and uncles, or family friends. It can be as simple as setting up a fundraising page and sharing with your network through email and social media.  Or it can be an in-person event such as a gala, a happy hour, a picnic, or cocktails in your home. The options are limitless and we are here to help you every step of the way. We can help you with graphic design, save the dates/invitations, e-blasts, an event webpage, and more. Set up your fundraising page today or contact info@fpwr.org to get started!

2021 Impact SYS 6

Download our Schaaf-Yang Syndrome Research Program Impact Report.

SYS Family Conference

FPWR's Schaaf-Yang Family Conference is held in conjunction with our PWS Family Conference and Research Symposium. This powerful experience combines education, networking and community-building. Learn the latest in Schaaf-Yang research from experts in the field and have the opportunity to engage one-on-one with the researchers that have a deep interest in finding treatments for our loved ones with Schaaf-Yang. Please watch our list of events for details of upcoming events.

SYS Research


SYS Your Funds At Work


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