Notably, metformin treatment had the greatest capacity to reduce insulin secretion, AMH levels and ovarian volume in the hyperinsulinemic group of obese PCOS patients compared to normoinsulinemic obese patients, in which metformin-improved insulin sensitivity and testosterone levels did not lead to these other changes (Romualdi et al. 2011). The gene discussed is INS; the disease is polycystic ovary syndrome.