When comparing the frequencies between the lean and obese PCOS groups, the lean PCOS patients demonstrated significantly higher frequencies of CYP21A2 c.552 C > G (p. D184E) compared with the obese PCOS patients (8.2% vs. 0%, P = 0.006; see Supplementary Fig. S3 and Table S5), while no significant differences were found in CYP17A1 and HSD3B2. The gene discussed is CYP21A2; the disease is polycystic ovary syndrome.