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, which may improve the lives of individuals with both SYS and PWS. Click here to learn more about MAGEL2 research funded by FPWR or read our SYS Research Plan.

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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.

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 diagnoses 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.

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 >>


Further information on the diagnosis and recommendations for care can be found on the Magel2 portal. Diagnosed families are encouraged to contact Dr. Christian Schaaf at schaaf@bcm.edu

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.You can help advance SYS research. Get Started!

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 sarah.peden@fpwr.org to get started!

2019 SYS Revenue Facts


SYS Family Conference

FPWR's Biannual 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. Due to the COVID-19 pandemic, our 2020 conference will take place virtually October 2020. Please watch our list of events for details of upcoming events. 

SYS Research Plan

A research plan has been developed to help guide FPWR’s SYS research program over the next 3 years. This plan was developed through the input of experts as well as advocates from the SYS community. It includes a brief description of the ‘current state of research,’ as well as highlights current opportunities and needs, and identifies and prioritizes key research questions. Learn more about our plans for 2019 and how YOU can make it happen for SYS!

Donate for SYS

Download the SYS Research Plan


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