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ICD-9-CM Code

  • 759.81 Prader-Willi syndrome1

ICD-10-CM Code

  • Q87.1 Congenital malformation syndromes predominantly associated with short stature2

Preferred Practice Pattern

Key Features


  • Lack of impression from several imprinted genes3

  • Genetic disorder characterized by

    • Specific facial features such as almond shaped eyes

    • Hypotonia

    • Hypogonadism

    • Strabismus5

    • Short stature

    • Cognitive deficits

    • Inability to regulate appetite

    • Males with undescended testicles6

    • Small hands and feet5,6

Essentials of Diagnosis

  • Two stages3,4

    • Stage 1 occurs during infancy with hypotonia and poor suck/swallow reflex that may result in failure to thrive

    • Stage 2 generally begins about 2 years of age with lack of satiety progressing to obesity

General Considerations

  • Growth hormone deficiency5

  • Patients often develop complications from obesity and osteoporosis as they age8


  • 1 in 15,000 individuals4

  • Affects females and males equally

Clinical Findings

Signs and Symptoms

  • Poor suck/swallow ability at birth

  • Hypotonia in infancy

  • Specific facial features such as almond shaped eyes

  • Hypogonadism

  • Strabismus5

  • Short stature

  • Obesity

  • Cognitive deficits

  • Inability to regulate appetite

  • Hypogenitalism; males with undescended testicles6

  • Small hands and feet5,6

  • Developmental delay

Functional Implications

  • May require gastrostomy tube5

  • Cognitive impairment

  • Learning disabilities

  • Poor speech articulation

  • Behavioral problems7

  • Obsessive-compulsive disorder7

  • Scoliosis7

Possible Contributing Causes

  • Deletion in portion of chromosome 15q115

  • Possibly due to dysfunction of hypothalamus4

Differential Diagnosis8

  • Obsessive-compulsive disorder

  • Failure to thrive

  • Fragile X syndrome

  • Growth hormone disorder

Means of Confirmation or Diagnosis

Laboratory Tests

  • DNA methylation analysis4,5

  • Magnetic resonance imaging (MRI) to assess pituitary gland8


  • Fluorescence in situ hybridization (FISH)

  • Chromosomal Microarray Analysis (CMA)

  • Standard radiograph to screen for scoliosis

Findings and Interpretation

  • Deletion in portion of chromosome 15q11 detected by FISH or microarray3



  • Human growth hormones 8

    • Saizen

    • Genotropin

    • Humatrope

    • Nutropin

    • Serostim


  • Orthopedist for possible scoliosis

  • Endocrinologist

  • Geneticist

  • Nutritionist

  • Ophthalmologist

  • Gastroenterologist

  • Psychiatrist

  • Occupational therapist

  • Speech therapist


  • Poor head control

  • Poor trunk control

  • Inability to sit independently

Tests and Measures

  • Bayley Scales ...

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