Sanfilippo Syndrome: Profound Deficiency of Alpha-Acetylglucosaminidase Activity in Organs and Skin Fibroblasts from Type-B Patients

Cultured skin fibroblasts from two patients with Sanfilippo syndrome, Type B were strikingly deficient in α-acetylglucosaminidase activity (α-2-acetamido-2-deoxy-D-glucoside acetamidodeoxyglucohydrolase, EC 3.2.1.X). A similar deficiency was found in frozen organs from two other patients. A partial deficiency of α-acetylglucosaminidase was found in cultured skin fibroblasts from both parents of one patient. Soluble endogenous inhibitors did not account for the enzyme deficiency. Other lysosomal hydrolases were normal or increased in cultured fibroblasts from patients with this disease. No deficiency of α-acetylglucosaminidase is present in other genetic mucopolysaccharidoses, including Sanfilippo Type A.