Nationwide carrier screening for congenital adrenal hyperplasia: integrated approach of CYP21A2 pathogenic variant genotyping and comprehensive large gene deletion analysis.

Background: Congenital Adrenal Hyperplasia (CAH) due to 21-hydroxylase deficiency (21-OHD CAH) is an autosomal recessive disorder resulting from pathogenic variants in the CYP21A2 gene. The disorder exhibits variable clinical severity, with the classical form manifesting as salt-wasting crisis in neonates, while inducing ambiguous genitalia in females and precocious puberty in males through simple virilization. Identifying at-risk couples during the preconception stage holds significance for optimizing reproductive choices.