PDHB and Alzheimer disease: A closer examination of the top downregulated genes belonging to this pathway revealed that genes linked to pyruvate dehydrogenase activity (PDHB, DLD, and PDHA1), mitochondrial β-oxidation (ACADS, ETFA, ETFB, ECHS1, PCCA, PCCB, ACAT2, and ACOT8), and mitochondrial fatty acid synthesis (AASDHPPT, ACACA, MCAT, MECR, NDUFAB1, OXSM) were downregulated in AD brains compared to controls.