CYP21A2 and congenital adrenal hyperplasia: Among 46, XX individuals with genital anomalies, 90%–95% of cases are associated with congenital adrenal hyperplasia (CAH) caused by CYP21A2 deficiency, and patients may present with varying degrees of external genital masculinization in infancy and early childhood and primary amenorrhea or infertility in adolescence or adulthood (Speiser et al., 2018).