NR4A2 and obesity due to melanocortin 4 receptor deficiency: We found that several variants located in nicotinamide adenine dinucleotide (NADH) dehydrogenase subunit (MT-ND1, MT-ND4, and MT-ND5) genes, respiratory complex I, and mitochondrial 12S and 16S ribosomal RNA (MT-RNR1 and MT-RNR2) genes were significantly positively or negatively correlated with risk of obesity.