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.
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.
Because MAGEL2 is one of the key genes involved in PWS, the Foundation for Prader-Willi Research (FPWR) has funded a number of studies to understand how MAGEL2 normally functions, and how loss of MAGEL2 function causes the symptoms associated with SYS and PWS.
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.
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.
Publication Documents the Similarities and Differences Between PWS and SYS
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.
Schaaf-Yang Syndrome 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!
For Further Information
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