Morquio A disease (or mucopolysaccharidosis IVA; MPS IVA) [3,4], is caused by the deficiency of lysosomal enzyme N-acetylgalactosamine 6-sulphatase (GALNS, E.C.3.1.6.4) [5], which leads to a progressive accumulation of the substrate of the enzyme at the cellular level in different tissues, such as bone and cartilage [6,7,8,9,10]. This evidence concerns the gene GALNS and mucopolysaccharidosis type 4A.