GALNS and mucopolysaccharidosis type 4A: Morquio A syndrome, or mucopolysaccharidosis type IVA (MPS IVA, OMIM #253000), is an autosomal recessive disease, caused by mutations in the N-acetylgalactosamine-6-sulfatase (GALNS), gene which result in deficient activity of N-acetylgalactosamine-6-sulfatase (GALNS, E.C.3.1.6.4), an enzyme that degrades glycosaminoglycan (GAG) keratan sulate (KS) and chondroitin-6-sulfate (C6S) [1,2].