TNXB and Ehlers-Danlos syndrome: Tenascin-X was the first structural protein beyond fibrillar collagens or their modifying enzymes associated with EDS and to investigate its hitherto unknown functions, two groups independently created homozygous Tnxb knockout (Tnxb–/–) mice (Matsumoto et al., 2001; Mao et al., 2002).