SDHB and Alzheimer disease: We analyzed the expression of three gene transcripts ND1, (encoding NADH dehydrogenase subunit 1), CO1 and CO3 (encoding cytochrome c oxidase subunit 1 and 3, respectively), as well as several mitochondria respiratory chain subunits (CI-NDUFB8, CII-SDHB, CIV-MTCO1, CV-ATP5A) in 3x Tg-AD mice (Supplementary Figs. S3 and S4).