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Prader-Willi syndrome

Suzanne B Cassidy1, Stuart Schwartz, Jennifer L Miller

  • 1Division of Medical Genetics, Department of Pediatrics, University of California, San Francisco, San Francisco, California, USA. suzannecassidy@comcast.net

Genetics in Medicine : Official Journal of the American College of Medical Genetics
|January 13, 2012
PubMed

Insights

Prader-Willi syndrome is a genetic disorder affecting development, characterized by hypotonia, obesity, and developmental delays. Genetic testing, including DNA methylation analysis, is crucial for diagnosis and understanding the molecular basis.

Area of Science:

  • Genetics
  • Pediatrics
  • Endocrinology

Background:

  • Prader-Willi syndrome presents with a complex phenotype including hypotonia, hypogonadism, obesity, developmental delay, and distinct facial features.
  • Sleep abnormalities and scoliosis are common comorbidities, and growth hormone insufficiency is frequently observed.

Purpose of the Study:

  • To outline the key clinical characteristics and diagnostic criteria for Prader-Willi syndrome.
  • To detail the genetic underpinnings of Prader-Willi syndrome, including common molecular classes.
  • To emphasize the importance of genetic testing for accurate diagnosis and management.

Main Methods:

  • Diagnosis relies on consensus clinical criteria, confirmed by genetic testing.
  • Genetic testing includes parent-specific DNA methylation analysis to detect >99% of cases.
  • Further genetic studies are needed to identify specific molecular classes, such as deletions, uniparental disomy, or imprinting defects.

Main Results:

  • Prader-Willi syndrome is caused by the absence of paternally expressed imprinted genes at 15q11.2-q13.
  • The most common genetic causes are paternal deletion (65-75%) and maternal uniparental disomy 15 (20-30%).
  • Absence of the SNORD116 gene is implicated in many clinical features.

Conclusions:

  • Accurate diagnosis of Prader-Willi syndrome requires genetic confirmation.
  • Understanding the molecular basis is essential for comprehensive management and genetic counseling.
  • While sibling recurrence risk is low, prenatal diagnosis is available.

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