Summary: CRISPR/Cas9 genome-engineered Chst14−/− mouse models of musculocontractural Ehlers-Danlos syndrome (mcEDS) display similar myopathic features (particularly those caused by the loss of D4ST1) to mcEDS patients and may facilitate further understanding of mcEDS. The gene discussed is CHST14; the disease is Ehlers-Danlos syndrome, musculocontractural type.