GAGs and GLs account for the mucopolysaccharidoses (MPS) and metachromatic leukodystrophy, respectively. Deficiencies in non-lysosomal sulfatases, arylsulfases C and E, cause X-linked ichthyosis (XLI) and chondrodysplasia punctata (CDPX), respectively.
Mammalian sulfatases have a common CXPXR motif, in which the Cys residue is post-translationally modified to a Ca-formylglycine (FGly) residue. This modification is essential for catalytic activity of all sulfatases and is catalyzed by FGly generating enzyme (FGE) encoded by sulfatase modifying factor (SUMF). FGE deficiency is the reason for multiple sulfatase deficiency (MSD), a rare autosomal recessive disorder.