Sulfamidase (SGSH) in MPSIIIA, N-acetylglucosaminidase (NAGLU) in MPSIIIB, Acetyl-Coα-glucosaminide acetyltransferase (HGSNAT) in MPSIIIC and N-acetylglucosamine 6-sulfatase (GNS) in MPSIIID. The gene discussed is SGSH; the disease is mucopolysaccharidosis type 3D.