With ageing being the strongest risk factor, several genetic polymorphisms in various gene loci have been associated with increased AD risk, such the Apolipoprotein E4 (ApoE4) allele or the R47H mutation in Trem2 (Roses, 1996; Guerreiro et al., 2013; Jonsson et al., 2013). The gene discussed is APOE; the disease is Alzheimer disease.