Mucopolysaccharidosis IV A (MPS IVA, MPS4A, Morquio's syndrome, Morquio's; MIM:253000) is a rare, autosomal recessive mucopolysaccharide storage disease, first described simultaneously in 1929 by L Morquio (Morquio L, Sur une forme de distrophie familiale, Bull Soc Pediat, Paris, 27, 1929, 145-152) and JF Brailsford (Brailsford, JF, Chondro-osteo-dystrophy: roentgenographic and clinical features of child with dislocation of vertebrae, Am j Surg, 7, 1929, 404-410). MPSIVA is caused by a deficiency in N-acetylgalactosamine 6-sulfatase (GALNS; MIM:612222) which normally hydrolyses 6-sulfate groups of N-acetylgalactosamine 6-sulfate units of chondroitin sulfate (CS) and of galactose 6-sulfate units of keratan sulfate (KS) (Matalon et al. 1974). The result is accumulation of KS/DS in cells and overexcretion in urine. Severe osteochondrodysplasia is a commonly seen phenotype for this disease. The severity of the disease is variable but severe cases limits lifespan to their 20's or 30's (Prat et al. 2008, Tomatsu et al. 2011). The gene coding for human GALNS was mapped to chromosome 16q24.3 (Masuno et al. 1993) and its structure described at the same time by two independent groups as comprising 14 exons and spanning approximately 40-50 kb (Nakashima et al.1994, Morris et al.1994).