Moreover, 2-oxoglutarate dehydrogenase (OGDHL, DLD), succinyl-CoA ligase (SUCLA2, SUCLG1), succinate dehydrogenase [succinate dehydrogenase [ubiquinone] flavoprotein subunit (SDHA), succinate dehydrogenase [ubiquinone] iron-sulfur subunit (SDHB), SDHC], fumarase (FH), and malate dehydrogenase (MDH1, MDH2) were significantly decreased in multiple brain regions of AD. Here, MDH1 is linked to Alzheimer disease.