CHST14 and Ehlers-Danlos syndrome: Musculocontractural Ehlers–Danlos Syndome (mcEDS) is a type of EDS, caused by biallelic pathogenic variants in the gene for carbohydrate sulfotransferase 14/dermatan 4-O-sulfotransferase 1 (CHST14/D4ST1, mcEDS-CHST14) (MIM#601776), or in the gene for dermatan sulfate epimerase (DSE, mcEDS-DSE) (MIM#615539) [1,2,3].