APOE and Alzheimer disease: Gibson and colleagues reported that mitochondrial dysfunctionwas more common in the brains of AD patients with the APOE ε4 allele [227].The mechanisms explaining this association are not completely understood but thereis some evidence to suggest that the neurotoxicity stems at least in part from theentry of ApoE4 isoform fragments into the cytosol and ultimately intomitochondrial membranes [184].