Schaaf-Yang syndrome related MAGEL2 gene is located on chromosome 15.
Schaaf-Yang syndrome is a rare genetic disorder characterized by hypotonia(low muscle tone), developmental delay, intellectual disability, and an autism spectrum disorder.

Genetic variants that occur in MAGEL2 gene on chromosome 15 cause the syndrome.
The syndrome is also known to share similar features with Prader-Willi syndrome, for their genetic causes and symptoms are similar to each other.


Map background with the silhouette of a fetus and words saying "The prevalence of Schaaf-Yang syndrome is less than 1 in 1,000,000 worldwide."


The prevalence of Schaaf-Yang syndrome is less than 1/1,000,000 worldwide.


The symptoms of Schaaf-Yang syndrome are usually present from the uterus.
Upon severity of the symptoms, some babies can die in utero from fetal akinesia and others can live with disabilities.


Seven symptoms of Schaaf-Yang syndrome: Hypotonia(low muscle tone), Feeding difficulties, Delayed psychomotor development, Impaired intellectual development, Autism spectrum disorder, Joint contractures, Variable dysmorphic facial features


The diagnosis of Schaaf-Yang syndrome is mostly based on clinical evaluation of presenting features and confirmation with genetic tests.

Whole Exome Sequencing & Single Gene Sequencing

Schaaf-Yang syndrome can be detected with single gene sequencing of the MAGEL2 gene. However, it is very rare for a physician to pinpoint the gene and conduct the testing.

Therefore, most cases are confirmed with whole exome sequencing by reading all protein-coding regions to find possible genetic causes.

To learn more about detailed diagnosis story of a boy with Schaaf-Yang syndrome, read Diagnosis story of a boy diagnosed with Schaaf-Yang syndrome.


Two family trees showing the autosomal dominant inheritance pattern of Schaaf-Yang syndrome in each case of parents affected.
Schaaf-Yang syndrome inherits in an autosomal dominant pattern.

However, the inheritance of the syndrome is significantly affected by the MAGEL2 gene's imprinting feature.

Most cases of Schaaf-Yang syndrome are from de novo mutation, and inheritance from the father follows next.


  1. ic-treatments-black@3x-3
  2. Currently, there is no treatment to cure Schaaf-Yang syndrome.
    Physical therapy, occupational therapy, and speech therapy are widely used to cope with developmental disabilities.
    To learn more about the Schaaf-Yang syndrome research plan, please visit the Foundation For Prader-Willi Research website(https://www.fpwr.org/about-schaaf-yang-syndrome).

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