Overview
Schaaf-Yang syndrome (SYS) is a rare genetic condition caused by changes (mutations) in the MAGEL2 gene, which is located on chromosome 15. This gene plays an important role in brain development and the function of the hypothalamus, a part of the brain that controls hunger, body temperature, hormones, and sleep. Schaaf-Yang syndrome shares some features with Prader-Willi syndrome but is a distinct condition with its own set of challenges. Babies with Schaaf-Yang syndrome often have low muscle tone (hypotonia) and difficulty feeding in the newborn period. As children grow, they may develop intellectual disability ranging from mild to severe, autism spectrum features, joint contractures (stiff or bent joints), and hormonal problems. Many children have distinctive facial features and small hands and feet. Unlike Prader-Willi syndrome, the extreme overeating (hyperphagia) seen in that condition is less common in Schaaf-Yang syndrome, though some individuals do develop increased appetite. There is currently no cure for Schaaf-Yang syndrome. Treatment focuses on managing individual symptoms through therapies such as physical therapy, occupational therapy, speech therapy, and hormone replacement when needed. A team of specialists typically works together to provide the best care. Research into this condition is ongoing, and understanding of the syndrome continues to grow as more patients are identified worldwide.
Also known as:
Key symptoms:
Low muscle tone (floppiness) in infancyFeeding difficulties in newbornsJoint contractures (stiff or bent fingers, wrists, or other joints)Intellectual disability (mild to severe)Autism spectrum behaviorsSpeech and language delaysSmall hands and feetHormonal problems (such as growth hormone deficiency)Sleep disturbancesDistinctive facial featuresDelayed motor milestones (sitting, walking)Temperature regulation problemsObesity or increased appetite in some individualsBehavioral challengesUnderdeveloped genitals in males (hypogonadism)
Clinical phenotype terms (50)— hover any for plain English
Autosomal dominant
Passed on from just one parent; each child has about a 50% chance of inheriting it
Neonatal
Begins at or shortly after birth (first 4 weeks)
FDA & Trial Timeline
1 eventHaukeland University Hospital — NA
Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.
Treatments
No FDA-approved treatments are currently listed for Schaaf-Yang syndrome.
View clinical trials →Clinical Trials
View all trials with filters →No actively recruiting trials found for Schaaf-Yang syndrome at this time.
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Treatment Centers
8 centersBaylor College of Medicine Rare Disease Center ↗
Baylor College of Medicine
📍 Houston, TX
🏥 NORDStanford Medicine Rare Disease Center ↗
Stanford Medicine
📍 Stanford, CA
🔬 UDNNIH Clinical Center Undiagnosed Diseases Program ↗
National Institutes of Health
📍 Bethesda, MD
🔬 UDNUCLA UDN Clinical Site ↗
UCLA Health
📍 Los Angeles, CA
🔬 UDNBaylor College of Medicine UDN Clinical Site ↗
Baylor College of Medicine
📍 Houston, TX
🔬 UDNHarvard/MGH UDN Clinical Site ↗
Massachusetts General Hospital
📍 Boston, MA
🏥 NORDMayo Clinic Center for Individualized Medicine ↗
Mayo Clinic
📍 Rochester, MN
👤 Mayo Clinic Center for Individualized Medicine
🏥 NORDUCLA Rare Disease Day Program ↗
UCLA Health
📍 Los Angeles, CA
Travel Grants
No travel grants are currently matched to Schaaf-Yang syndrome.
Community
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Caregiver Resources
NORD Caregiver Resources
Support, advocacy, and financial assistance for caregivers of rare disease patients.
Mental Health Support
Rare disease caregiving can be isolating. Connect with counseling and peer support.
Family & Caregiver Grants
Financial assistance programs specifically for caregivers of rare disease patients.
Social Security Disability
Learn how rare disease patients may qualify for SSDI/SSI benefits.
Questions for your doctor
Bring these to your next appointment
- Q1.What specific MAGEL2 mutation does my child have, and what does it mean for their expected symptoms?,Should my child be tested for growth hormone deficiency, and would growth hormone therapy be beneficial?,What therapies (physical, occupational, speech) should we start, and how often?,Are there any clinical trials or research studies for Schaaf-Yang syndrome that we could participate in?,How should we monitor for hormonal problems, sleep issues, and other complications over time?,What is the risk of having another child with this condition, and should we pursue genetic counseling?,Are there any specific emergency situations we should be prepared for, and what should our action plan be?
Common questions about Schaaf-Yang syndrome
What is Schaaf-Yang syndrome?
Schaaf-Yang syndrome (SYS) is a rare genetic condition caused by changes (mutations) in the MAGEL2 gene, which is located on chromosome 15. This gene plays an important role in brain development and the function of the hypothalamus, a part of the brain that controls hunger, body temperature, hormones, and sleep. Schaaf-Yang syndrome shares some features with Prader-Willi syndrome but is a distinct condition with its own set of challenges. Babies with Schaaf-Yang syndrome often have low muscle tone (hypotonia) and difficulty feeding in the newborn period. As children grow, they may develop int
How is Schaaf-Yang syndrome inherited?
Schaaf-Yang syndrome follows a autosomal dominant inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
At what age does Schaaf-Yang syndrome typically begin?
Typical onset of Schaaf-Yang syndrome is neonatal. Age of onset can vary across affected individuals.
Which specialists treat Schaaf-Yang syndrome?
15 specialists and care centers treating Schaaf-Yang syndrome are listed on UniteRare, sourced from ClinicalTrials.gov principal investigators, published research, and the NPPES NPI registry.