GALNS and mucopolysaccharidosis type 4A: MPS II, MPS IIID, MPS IVA, and MPS VI are caused by deficiencies in sulfatases (IDS, N-acetyl glucosamine-6-sulfatase, N-acetyl galactosamine-6-sulfatase, and N-acetyl galactosamine 4-sulfatase, respectively); MPS IIIA is caused by deficiency in a sulfamidase (N-sulfoglucosamine sulfohydrolase; SGSH); and MPS IIIC is caused by deficiency in an acetyl transferase (α-glucosaminide N-acetyl transferase; HGSNAT).