DSE and connective tissue disorder: Musculocontractural EDS (mcEDS) is a hereditary connective tissue disorder with autosomal recessive inheritance, associated with generalized depletion of dermatan sulfate (DS), which is caused by defective activity of dermatan 4-O-sulfotransferase 1 (D4ST1) or dermatan sulfate epimerase (DSE) through biallelic loss-of-function variants in the carbohydrate sulfotransferase gene (CHST14) (mcEDS-CHST14) (MIM#601776) or in the gene encoding DSE (DSE) (mcEDS-DSE) (MIM#615539), respectively [3].