The function of ENSG00000100299 (ARSA, arylsulfatase A) is as follows. Lysosomal enzyme that catalyzes the hydrolysis of cerebroside-3-sulfate (sulfatide) into cerebroside and sulfate, a reaction that requires the activator protein saposin B. {ECO:0000269|PubMed:10751093, ECO:0000269|PubMed:19224915, ECO:0000269|PubMed:24294900}.