These variables that adversely affect endocrine-metabolic function in PCOS were avoided in our studies by investigating healthy, normal-weight PCOS women by NIH criteria who were recruited from the general population to study a mild PCOS phenotype [17, 20] and who also were age- and BMI-balanced to controls to eliminate the effects of age and obesity on metabolic outcomes, including insulin sensitivity [15, 16, 19, 21]. The gene discussed is INS; the disease is obesity due to melanocortin 4 receptor deficiency.