Here, we found that pyruvate dehydrogenase related genes PDHA1, PDHB, PDHX, DLAT showed consistent down-regulation in AD brain and blood cells, suggesting that pyruvate dehydrogenase deficiency may participate in AD-like nerve injury by regulating acetyl-CoA production leading to TCA cycle and acetylcholine production disorder. The gene discussed is PDHX; the disease is Alzheimer disease.