Tenascin-R (TNR) is an extracellular matix protein expressed primarily in the central nervous system. It is a member of the tenascin (TN) gene family, which includes at least 3 genes in mammals: TNC (or hexabrachion; MIM 187380), TNX (TNXB; MIM 600985), and TNR (Erickson, 1993 [PubMed 7694605]). The genes are expressed in distinct tissues at different times during embryonic development and are present in adult tissues.