Mucopolysaccharidosis type IVA (MPS IVA; Morquio A syndrome) is an autosomal recessive lysosomal storage disorder caused by deficiency of N-acetylgalactosamine-6-sulfatase (GALNS), an enzyme essential for the degradation of keratan sulfate and chondroitin-6-sulfate [1]. Here, GALNS is linked to mucopolysaccharidosis type 4A.