Leptin is an adipokine predominately expressed in subcutaneous adipocytes [45], and one may speculate that gender differences in subcutaneous fat accumulation [46], leptin resistance [47] and sex hormone levels [20], [22], [23] may contribute to the observed differences in obesity-related susceptibility to colonization between women and men. The gene discussed is LEP; the disease is obesity due to melanocortin 4 receptor deficiency.