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Prader-Willi syndrome

Last reviewed: 4 Nov 2023
Last updated: 20 Jun 2023



History and exam

Key diagnostic factors

  • central hypotonia
  • poor suck
  • weak cry
  • feeding difficulties
  • hypogonadism
  • weight gain and hyperphagia
More key diagnostic factors

Other diagnostic factors

  • developmental delay
  • cognitive disability
  • endocrine disorders
  • sleep abnormalities
  • behavioral abnormalities
  • psychiatric disorders
  • short stature
  • small hands and feet
  • hypopigmentation
  • ocular problems
  • spinal deformities
  • polyhydramnios
  • decreased fetal movements
  • developmental dysplasia of the hip
  • seizures
  • premature adrenarche
Other diagnostic factors

Risk factors

  • older maternal age (>35 years)
  • hydrocarbon exposure
  • conception using assisted reproductive technology
  • sibling with Prader-Willi syndrome (PWS)
More risk factors

Diagnostic investigations

1st investigations to order

  • DNA methylation testing
More 1st investigations to order

Investigations to consider

  • further genetic testing
More investigations to consider

Treatment algorithm


with acute illness


without acute illness



Jennifer Miller, MD

Professor of Pediatric Endocrinology

University of Florida




JM declares that she has no competing interests.

Peer reviewers

Nicola Bridges, DM, MRCP, FRCPCH

Consultant Paediatric Endocrinologist

Chelsea and Westminster Hospital




NB declares she has no competing interests.

  • Prader-Willi syndrome images
  • Differentials

    • Spinal muscular atrophy
    • Angelman syndrome
    • Temple syndrome
    More Differentials
  • Guidelines

    • Guides for doctors: consensus documents
    • Health supervision for children with Prader-Willi syndrome
    More Guidelines
  • Patient leaflets

    Weight problems in adults: questions to ask your doctor

    Weight problems in children: changing unhealthy habits

    More Patient leaflets
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