CYP21A2 and congenital adrenal hyperplasia: It has been reported that heterozygous TNXB mutations may be associated with the mild joint hypermobility form of EDS [1, 15] and that up to 10% of classic SW-CAH patients harboring in compound heterozygosity a TNXB/CYP21A2 genotype tend to demonstrate an extended phenotype termed CAH-X syndrome [1, 31, 32] (Fig. 2).