As for the variant located in the Complex I gene, MT-ND5(13135), it presented interactions with variants in genes encoding Complexes I (one variant in MT-ND2 and one in MT-ND3), III (two variants in MT-CYB) and IV (one variant in MT-COX1; notably, specific genotypes of MT-COX1(7476) and MT-CYB(15257) jointly with the GG genotype for MT-ND5(13135) may affect TAU levels in both cognitively healthy and AD individuals, and the same pattern was observed for MT-ND3(10172) in MCI patients. The gene discussed is MT-ND2; the disease is Alzheimer disease.