ARSG and mucopolysaccharidosis-plus syndrome: They include types I, II, IIIA, IIIB, IIIC, IIID, IIIE (recognized recently as a deficiency in arylsulfatase G, encoded by the ARSG gene [5,6]), IVA, IVB, VI, VII, IX, X (the latest types described [7]), and MPSPS (MPS-Plus syndrome, caused by mutations in the VPS33A gene rather than in a gene coding for a lysosomal hydrolase, but resulting in massive GAG accumulation [8,9]).