The metabolic traits associated with obesity may be inter-correlated to various extents, but according to a recent twin study [24], there is little common underlying genetic or shared environmental etiology behind these correlations, which we think justifies the separate analysis of each of the traits as we have conducted here barring the analyses where we examined if the total body fatness could explain the observed association between FTO and other traits. The gene discussed is FTO; the disease is obesity due to melanocortin 4 receptor deficiency.