Down's syndrome Trisomy 21

• Facts:
  MC chromosomal disorder and cause of mental retardation
  
  In addition to trisomy 21, may be caused by Robertsonian translocation
• History / PE:
  Head and neck
  Brachycephaly
  Upslanting palpebral fissures
  Epicanthic folds
  Brushfield spots
  Flat nasal bridge
  Folded or dysplastic ears
  Small ears
  
• Diagnosis:
  Antenatal evaluation ( QUAD screen )
  Increased inhibin A, β hCG
  Decreased MSAFP, estriol
• Complications:
  Pulmonary hypertension (from endocardial cushion defects)
• See Also:
  Edward's syndrome (trisomy 18)
  Patau's syndrome (trisomy 13)
• Associated With:
  1) Duodenal atresia
  2) Hirshsprung's disease
  3) Atrioventricular canal (ASD, VSD from endocardial cushion defects)
  4) Increased risk of acute lymphocytic leukemia (ALL)
  5) Hypothyroidism
  6) Early onset Alzheimer's
  7) Atlantoaxial instability (UMN findings)
  8) GERD