Gao Y, Lu L, Yu B, et al. - In the present study, the researchers sought to evaluate the prevalence of the chimeric TNXA/TNXB gene and clinical symptoms in a Chinese cohort with 21-hydroxylase deficiency (21-OHD). Participants in the study were 424 patients with 21-OHD who were genetically diagnosed. In order to identify the CAH-X genotype, multiplex ligation-dependent probe amplification and sequencing were used. Clinical features of joints, skin, and other systems have been assessed in 125 patients. Of the 424 patients, 94 had a deletion on at least 1 allele of CYP21A2 and 59 of them harbored the heterozygotic TNXA/TNXB chimera. Approximately 14% of patients with 21-OHD in the study may have chimeric TNXA/TNXB gene mutations and most of them have clinical symptoms associated with EDS. It is important to further examine the association between the CAH-X genotypes and clinical features in connective tissue, such as joint or skin.