In the case of familial AD, represents 2% of diagnosed cases, the cognitive decline begins at 40 years old due to mutation in APP gene (chromosome 21), presenilin-1 (PS1, chromosome 14), and presenilin-2 (PS2, chromosome 1), triggering Aβ42 generation, while sporadic AD is subdivided into early onset if the symptoms begin under 65 years of age (3–5% prevalence) with the rest of the cases represented as late onset (95–97% prevalence) due to e4 allele of the APOE gene (chromosome 19) (Folch, Petrov et al., 2016). The gene discussed is PSEN2; the disease is Mental deterioration.