Mucopolysaccharidosis type IVA (MPS IVA or Morquio A syndrome) is an autosomal recessive lysosomal disorder caused by mutations in the N-acetyl-galactosamine-6-sulfate sulfatase (GALNS) gene, leading to a deficiency of the GALNS enzyme [1,2,3,4,5]. This evidence concerns the gene GALNS and mucopolysaccharidosis type 4A.