GALNS and mucopolysaccharidosis type 4B: Mucopolysaccharidosis IV (Morquio syndrome) is an autosomal recessive disease that is split into two different subtypes, MPS IVA and MPS IVB, with deficiency of N-acetylgalactosamine-6-sulfatase (GALNS) and β-galactosidase, respectively (Table 1) [1,2].