Appears to mediate interactions between cells and the extracellular matrix. Substrate-adhesion molecule that appears to inhibit cell migration. Accelerates collagen fibril formation. May play a role in supporting the growth of epithelial tumors. Homotrimer. Interacts with type I, III and V collagens and tropoelastin via its 29th fibronectin type-III domain. Highly expressed in fetal adrenal, in fetal testis, fetal smooth, striated and cardiac muscle. Isoform XB-short is only expressed in the adrenal gland. Expression levels are lower in adults than in children. The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. May be due to competing acceptor splice site in exon 24. May be due to competing donor splice site in exon 1. Belongs to the tenascin family. There are two genes for TN-X: TNXA and TNXB. TNXA can sometimes recombine with TNXB.