Handbook of Genetic Counseling/Sanfilippo syndrome

Sanfilippo syndrome

Other names: Mucopolysacchardosis III, Type A, B, C, and DEdit

  • So, it is a syndrome in which the large saccharides are not broken down properly in the lysosomes. It's a lysosomal storage deficiency.


  • Most common of the MPS diseases
  • Normal to fast growth 1-3 years. Slow growth after that.
  • Slow development by 1-3 years then deterioration
  • Short stature
  • Hearing loss
  • Poor gait
  • Poor speech
  • Poor behavior
  • Synophrys (joined eyebrows)
  • Mild cardiac involvement
  • Clear corneas
  • Sleep disturbances
  • Upper respiratory tract infections
  • Many die of pneumonia (10-20 years)


  • Autosomal recessive in all types
  • Sanfilippo A = defect in heparan N-sulfatase
  • Sanfilippo B = deficiency in N-acetyl-alpha-delta glucosaminidase
  • Sanfilippo C = deficiency of acetyl-CoA: alpha-glucosaminide-N-acetyltransferase
  • Sanfilippo D = deficiency of N-acetyl-alpha-delta glucosaminide-6-sulfatase


  • By clinical features mentioned above (same for all four types except type D)
    • Overactivity
    • Destructive tendencies
    • Weakness in all extremities
  • Presence of excess heparan sulfate in the urine


  • National MPS Society
102 Aspen Drive


The information in this outline was last updated in 2000.