Carbohydrate sulfotransferase 14 (CHST14) (Evers et al. 2001) mediates the transfer of sulfate to position 4 of N-acetylgalactosamine (GalNAc) residue of dermatan or to a further GalNAc residue of dermatan sulfate (D2,4(S)2-PG) in iduronate rich domains. As 4-O sulfation by CHST14 is essential for DS formation, defective CHST14 results in much lower levels of DS and higher levels of chondroitin sulfate (CS) being produced. DS plays an important role in human development and extracellular matrix maintenance and defective CHST14 results in Ehlers-Danlos syndrome, musculocontractural type (MIM:601776). Mutations causing this disease include V49*, R213P, R135G/L137Q, Y293, P281L and the compound heterozygotes P281L/K69* and P281L/C285S (Dundar et al. 2009, Miyake et al. 2010).