In humans, full-heritage PIMA Indians are associated with a high incidence of obesity and type 2 diabetes [78,79], and a subset analysis showed that endogenous plasma EPO level exhibited an inverse association with percent weight change per year among males that was not evident in females and was not dependent on EPO regulation of erythropoiesis [80]. The gene discussed is EPO; the disease is obesity due to melanocortin 4 receptor deficiency.