<i>TNXB</i>-related classical-like Ehlers-Danlos syndrome (<i>TNXB</i>-clEDS) is an ultrarare type of Ehlers-Danlos syndrome due to biallelic <i>null</i> variants in <i>TNXB</i>, encoding tenascin-X.
EDS cells with COL5A1 haplo-insufficiency deposited less than one-half of hydroxyproline as collagen compared to control fibroblasts, though total collagen synthesis rates are near-normal because type V collagen represents a small fraction of collagen synthesized.
Ehlers-Danlos syndrome (EDS) type VIIC, or dermatosparactic type, is a recessively inherited connective tissue disorder characterized, among other symptoms, by an extreme skin fragility resulting from mutations inactivating ADAMTS-2, an enzyme excising the aminopropeptide of procollagens type I, II, and III.
Ehlers-Danlos syndrome (EDS) dermatosparaxis type (type VIIC) and the related disease of cattle dermatosparaxis, are recessively inherited connective tissue disorders, caused by a deficient activity of procollagen I N-proteinase, the enzyme that excises the N-terminal propeptide in procollagen type I, type II, and type III.
Ehlers-Danlos syndrome (EDS) type VII results from defects in the conversion of type I procollagen to collagen as a consequence of mutations in the substrate that alter the protease cleavage site (EDS type VIIA and VIIB) or in the protease itself (EDS type VIIC).
Ehlers-Danlos syndrome (EDS) type IV is a heritable disorder resulting from mutations in the COL3A1 gene that cause deficient production of type III collagen.
COL5A1 exon 14 splice acceptor mutation causes a functional null allele, haploinsufficiency of alpha 1(V) and abnormal heterotypic interstitial fibrils in Ehlers-Danlos syndrome II.
Tenascin-X is important for the proper deposition of collagen fibers in dermis and patients with a tenascin-X deficiency suffer from Ehlers Danlos syndrome.