Noonan Syndrome

• gene 12q24
• Autosomal dominant or sporadic
• General features: short stature, mental retardation, pectus excavatum, small penis, cryptorchidism, cubitus valgus
• Cardiac lesions
  • Esp. pulmonic stenosis. Also ASD.
• head/neck dysmorphisms
  • microcephaly
  • palpebral slant, hypertelorism, ptosis
  • broad, flat nose
  • malformed ears
  • high-arched palate
  • webbed neck, short neck, low hairline
• Also associated with Puberty, delayed

Noonan vs Turner Syndrome

• Main common findings
  • webbed neck/lymphedema
  • cubitus valgus
  • short stature
• main differential findings
  • more common in Noonan: pectus excavatum
  • Noonan-pulmonic stenosis; Turner-coarctation of aorta
  • Noonan-mental retardation.