GTR Home > Conditions/Phenotypes > Noonan syndrome 7

Disease characteristics

Excerpted from the GeneReview: Noonan Syndrome
Noonan syndrome (NS) is characterized by short stature, congenital heart defect, and developmental delay of variable degree. Other findings can include broad or webbed neck, unusual chest shape with superior pectus carinatum and inferior pectus excavatum, cryptorchidism, characteristic facies, varied coagulation defects, lymphatic dysplasias, and ocular abnormalities. Although birth length is usually normal, final adult height approaches the lower limit of normal. Congenital heart disease occurs in 50%-80% of individuals. Pulmonary valve stenosis, often with dysplasia, is the most common heart defect and is found in 20%-50% of individuals. Hypertrophic cardiomyopathy, found in 20%-30% of individuals, may be present at birth or develop in infancy or childhood. Other structural defects include atrial and ventricular septal defects, branch pulmonary artery stenosis, and tetralogy of Fallot. Up to one third of affected individuals have mild intellectual disability.

Associated genes

Clinical features

  • Short stature
  • Prominent forehead
  • Thickened helices
  • Intellectual disability
  • Dolichocephaly
  • Feeding difficulties in infancy
  • Hypertelorism
  • Low-set ears
  • Hyperpigmentation of the skin
  • Muscular hypotonia
  • Defect in the atrial septum
  • Pulmonic stenosis
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Go to complete MedGen record for Noonan syndrome 7

Clinical resources

Practice guidelines

  • AAP, 2010
    Noonan syndrome: clinical features, diagnosis, and management guidelines.
  • DYSCERNE, 2010
    DYSCERNE, Management of Noonan Syndrome. A Clinical Guideline by the Noonan Syndrome Guideline Development Group, 2010

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