Handbook of Genetic Counseling/Sanfilippo syndrome

Sanfilippo syndrome

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

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

Characteristics

• 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)

Genetics

• 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

Diagnosis

• 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

Resources

• National MPS Society

102 Aspen Drive

• Downingtown, PA 19335
• (610) 942-0100
• http://mpssociety.org/index.htm

Notes

The information in this outline was last updated in 2000.