Deficiency of arylsulfatase G (ARSG) leads to a lysosomal storage disease in mice resembling biochemical and pathological features of the mucopolysaccharidoses and particularly features of mucopolysaccharidosis type III (Sanfilippo syndrome).
Our results demonstrate the key role of ARSG in heparan sulfate degradation and strongly suggest that ARSG deficiency represents a unique, as yet unknown form of MPS, which we term MPS IIIE.