SGSH and mucopolysaccharidosis type 3A: MPS IIIA or Sanfilippo syndrome type A is caused by mutations in the SGSH gene, coding for sulfamidase (also known as heparan sulfate sulfatase or N-sulfoglucosamine sulfohydrolase, EC 3.10.1.1), which releases sulfate groups linked to the amino group of glucosamine.