CH-1 is characterized by a 120-bp deletion (c.11435_11524 + 30del) due to the substitution of TNXB exon 35 by TNXA that is causative of tenascin-X haploinsufficiency in CAH-X CH-1; this region is the only well-documented discrepancy between TNXB and TNXA homologous portion. This evidence concerns the gene TNXB and congenital adrenal hyperplasia.