In a genetic meta-analysis of AD patient cohorts, Sarajarvi and others found that a heterozygous DOR-Phe27Cys mutation increased the risk of AD, especially in late-stage AD patient postmortem brain samples in which there was a significant upregulation of BACE1 and γ-secretase activities (Sarajarvi et al., 2015). This evidence concerns the gene BACE1 and Alzheimer disease.