Mucopolysaccharidosis IVA (MPS IVA, Morquio A syndrome, Morquio–Brailsford syndrome, OMIM 253000), a lysosomal storage disease exhibiting an autosomal recessive inherited pattern, is caused by N-acetylgalactosamine-6-sulfatase enzyme deficiency (GALNS; EC 3.1.6.4) due to GALNS gene mutations located on chromosome 16q24 [1]. The gene discussed is GALNS; the disease is mucopolysaccharidosis type 4A.