Type III D mucopolysaccharidosis (Sanfilippo D): clinical course and symptoms.

A case of a rare form of Sanfilippo disease, mucopolysaccharidosis type III D is presented. The cause of the disease is a deficit of N-acetylglycosamine-6-sulfate sulfatase. Differences in clinical course and symptoms with type A and B Sanfilippo disease are shown (later presentation of symptoms, milder course, lack of distinct psychomotor regression and differences in characteristic phenotypic traits, such as facial features, joint contracture, tall height). It is suggested that type III D mucopolysaccharidosis be taken into account in the differentiation of mental retardation syndromes with hyperactivity.