Variants/defects throughout the entire 68 kb TNXB gene have been reported to cause hEDS [27]; however, those related to CAH-X mostly enrich within a 4.1 kb span of the TNXB 3′-end (exons 32–44) that shares 92% homology with TNXA [7,8,10,11,12,13]. This evidence concerns the gene TNXB and Ehlers-Danlos syndrome, hypermobility type.