Schaaf-Yang syndrome

What is Schaaf-Yang syndrome?

It is a rare genetic syndrome that is similar to Prader-Willi syndrome. It shares similar symptoms with the syndrome but minus the excessive appetite that accompanies Prader-Willi.

What gene changes cause Schaaf-Yang syndrome?

Mutations to the MAGEL2 gene on chromosome 15 cause the syndrome.
If this gene, along with several other genes, is missing it causes Prader-Willi syndrome. This is usually inherited in an autosomal dominant pattern, but most cases of the syndrome are de novo or new mutations.

In the case of autosomal dominant inheritance just one parent is the carrier of the gene mutation, and they have a 50% chance of passing it onto each of their children. Syndromes inherited in an autosomal dominant inheritance are caused by just one copy of the gene mutation.

In some cases, a genetic syndrome may be the result of a de-novo mutation and the first case in a family. In this case, this is a new gene mutation which occurs during the reproductive process.

What are the main symptoms of Schaaf-Yang syndrome?

The main symptoms of the syndrome, in infants especially, include low muscle tone as well as difficulties with feeding.

Developmental delay, intellectual disability and autism spectrum disorder are also associated with the syndrome.

Affected individuals may also have joint contractures- this usually involves permanently bent or permanently straightened joints in the finger. This can also affect the knees and elbows too.

How does someone get tested for Schaaf-Yang syndrome?

The initial testing for Schaaf-Yang syndrome can begin with facial analysis screening, through the FDNA Telehealth telegenetics platform, which can identify the key markers of the syndrome and outline the need for further testing. A consultation with a genetic counselor and then a geneticist will follow.

Get Faster and More Accurate Genetic Diagnosis!

More than 250,000 patients successfully analyzed!
Don't wait years for a diagnosis. Act now and save valuable time.

Start Here!

"Our road to a rare disease diagnosis was a 5-year journey that I can only describe as trying to take a road trip with no map. We didn’t know our starting point. We didn’t know our destination. Now we have hope."


Paula and Bobby
Parents of Lillie

What is FDNA Telehealth?

FDNA Telehealth is a leading digital health company that provides faster access to accurate genetic analysis.

With a hospital technology recommended by leading geneticists, our unique platform connects patients with genetic experts to answer their most pressing questions and clarify any concerns they may have about their symptoms.

Benefits of FDNA Telehealth


Our platform is currently used by over 70% of geneticists and has been used to diagnose over 250,000 patients worldwide.


FDNA Telehealth provides facial analysis and screening in minutes, followed by fast access to genetic counselors and geneticists.

Ease of Use

Our seamless process begins with an initial online diagnosis by a genetic counselor and follows by consultations with geneticists and genetic testing.

Accuracy & Precision

Advanced artificial intelligence (AI) capabilities and technology with a 90% accuracy rate for a more accurate genetic analysis.

Value for

Faster access to genetic counselors, geneticists, genetic testing, and a diagnosis. As fast as within 24 hours if required. Save time and money.

Privacy & Security

We guarantee the utmost protection of all images and patient information. Your data is always safe, secure, and encrypted.

FDNA Telehealth can bring you closer to a diagnosis.
Schedule an online genetic counseling meeting within 72 hours!