Mucopolysaccharidosis type 3

A group of rare lysosomal storage diseases characterized by progressive neurocognitive decline, loss of functional abilities and premature death. There are four etiological subtypes of mucopolysaccharidosis type 3 (MPS III, Sanfilippo syndrome) called Sanfilippo syndrome type A, B, C, and D. Each subtype is caused by deficiency of a particular enzyme involved in the degradation of heparan sulfate leading to substrate accumulation and cellular dysfunction.