2ND TRIMESTER PRENATAL-DIAGNOSIS OF SANFILIPPO SYNDROME TYPE-C

Sanfilippo syndromes or mucopolysaccharidosis type III are inherited d isorders that result from a deficiency in one of the four following ly sosomal enzymes involved in the degradation of heparan sulphate: hepar an sulphate sulphamidase (type A); N-acetyl-alpha-D-glucosaminidase (t ype B); acetyl-CoA: alpha-glucosaminide N-acetyltransferase (type C); and N-acetylglucosamine-6-sulphate sulphatase (type D). Patients excre te heparan sulphate in urine in excessive amounts. Discrimination betw een the four subtypes requires activity determination of the enzymes i nvolved since clinical and radiological symptoms are very similar (Mai re 1991). Sanfilippo syndrome type C seems less common than types A an d B (7 cases among 50 patients in our experience) and the number of ca ses reported so far is still limited (for review see Sewell et al 1988 ; Turki et al 1989).