CYP21A2 and classic congenital adrenal hyperplasia due to 21-hydroxylase deficiency: Given the high incidence and clinical severity of 21-OHD in China, developing of an NGS-based method capable of detecting a broad spectrum of CYP21A2 pathogenic variants, including large deletions, could significantly enhance the clinical utility of ECS (Wang et al., 2020; Umino et al., 2019; Simonetti et al., 2018).