CYP17A1 and classic congenital adrenal hyperplasia due to 21-hydroxylase deficiency: It mainly includes 21 hydroxylase deficiency, 11β-hydroxylase deficiency, 17α-hydroxylase/17, 20-lyase deficiency (17OHD) and congenital lipoid adrenal hyperplasia, among which 17OHD accounts for approximately 1%.[1] 17OHD is caused by mutation of the coding gene CYP17A1, which belongs to the member of 17 subfamily of cytochrome P450 superfamily (P450c17).