Specifically, both epidemiological and experimental studies demonstrated an association between persistent organic pollutant exposure and pathogenesis of obesity and this was due mainly to interference with adipogenesis through modulation of peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT/enhancer-binding protein (C/EBP) expression. The gene discussed is PPARG; the disease is obesity due to melanocortin 4 receptor deficiency.