In total, 1339 PCOS patients with a BMI<24 kg/m2 were grouped according to the serum AMH level: 1 <2.71 ng/ml (n=333), 2 2.71-4.08 ng/ml (n=330), 3 4.09-6.45 ng/ml (n=351), and 4 >6.45 ng/ml (n=325). This evidence concerns the gene AMH and polycystic ovary syndrome.