Molecular characterization of the new clinical entity associated with congenital adrenal hyperplasia: the CAH-X syndrome in the Spanish population

The chimeras causing the CAH-X syndrome (SCAH-X) result from recombination between CYP21A2-TNXB and their respective pseudogenes (CYP21A1P-TNXA). The clinical manifestations of this syndrome include congenital adrenal hyperplasia (CAH) and Ehlers–Danlos syndrome (EDS). Since SCAH-X has been recently described, the number of publications available is limited. The objective of this study was to set up a molecular approach and a screening algorithm for detecting CAH-X chimeras, determine their frequency and distribution in the Spanish population, and assess their clinical pattern of occurrence in a group of patients.