The GALNS gene codes for an enzyme called N-acetylgalactosamine 6-sulfatase that is located within lysosomes. This enzyme is involved in the degradation of the glycosaminoglycans (GAGs) or mucopolysaccharides, keratan sulfate, and chondroitin 6-sulfate.
Defects in this enzyme are the cause of Morquio A syndrome, a lysosomal storage disorder characterized by growth retardation; a prominent lower face, kyphoscoliosis, an abnormally short neck, knock knees, flat feet, epiphyses, pectus carinatum. Hearing loss, weakness of the legs, abnormal heart development, abnormal skeletal development and/or additional abnormalities may also occur.