Recently a report in JCI stated that Gpr54 knockout mice displayed a sexually-dimorphic metabolic phenotype, with male Gpr54−/− showed no alteration, but normal diet fed female Gpr54−/− mice ovariectomized at two weeks old developed obesity by 4–5 months of age. The gene discussed is KISS1R; the disease is obesity due to melanocortin 4 receptor deficiency.