Ehlers–Danlos Syndrome: Molecular and Clinical Characterization of <i>TNXA/TNXB</i> Chimeras in Congenital Adrenal Hyperplasia

Abstract Context The syndrome CAH-X is due to a contiguous gene deletion of CYP21A2 and TNXB resulting in TNXA/TNXB chimeras. Objective To analyze status clinically evaluate the Ehlers–Danlos phenotype large cohort Argentine congenital adrenal hyperplasia (CAH) patients assess prevalence this condition our population. Methods analysis was performed 66 nonrelated CAH that were carriers deletion. A molecular strategy based on multiplex ligation–dependent probe amplification Sanger sequencing developed allowing for detection different, previously described chimeras, named CH1, CH2, CH3. main outcome measures homozygous or heterozygous state. Results CH1 found 41%, CH2 29%, CH3 1% alleles carrying Thus, overall 71% carry Sixty-seven percent analyzed had monoallelic form 6% biallelic form. All with severe skin hyperextensibility generalized joint hypermobility. Conclusion Based high frequency alterations carrier alleles, we recommend evaluating these patients, assessing connective tissue dysplasia, including cardiologic positive cases. number undergoing cardiological evaluation should be expanded determine incidence structural functional abnormalities cohort.