MPS VI is caused by deficiency of the enzyme arylsulfatase B [ARSB] (N-acetylgalactosamine-4-sulfatase; EC 3.1.6.12) which removes the C4 sulfate ester group from the N-acetylgalactosamine sugar residue at the nonreducing terminus of the glycosaminoglycans dermatan sulfate and chondroitin sulfate (Neufeld and Muenzer 2001). This evidence concerns the gene ARSB and mucopolysaccharidosis type 6.