INSIG2 and obesity due to melanocortin 4 receptor deficiency: Most of the previous studies on INSIG2 rs766605 have been performed on patient cohorts or relatives of probands recruited because of end stage disease phenotypes such as hypertension, heart disease, cancer, type 2 diabetes mellitus and have used the relatively non-sensitive and non-specific phenotype of BMI as a measure for obesity [8-18].