APOE and Alzheimer disease: APOE has 3 isoforms that have allele‐specific effects (E2 > E3 > E4) in protecting neuronal cell lines from oxidative cell death.22 An interaction between APOE polymorphisms and mtDNA haplogroups in TBI has been described for AD in a cohort of 213 patients.23 In view of this, we analyzed a possible interaction between these factors in our cohort.