NAGLU and mucopolysaccharidosis type 3: MPS III (Sanfilippo syndrome) includes four distinct diseases (types A-D) resulting from a deficiency in one of the four enzymes involved in heparan sulfate degradation as follows: heparan N-sulfatase in type A (OMIM 252900), alpha-N-acetylglucosaminidase (NAGLU) in type B (OMIM 252920), acetyl CoA-alpha-glucosaminide acetyltransferase in type C (OMIM 252930), and N-acetylglucosamine 6-sulfatase in type D (OMIM 252940).