Due to mutations in APP and genetic risk genes, such as PSEN1 and PSEN2 which alter amyloid concentrations, patients with DS are more prone to develop Alzheimer’s disease at an earlier age (30–60 years) than those with late-onset Alzheimer’s disease (≥65 years) [122]. The gene discussed is PSEN1; the disease is early-onset autosomal dominant Alzheimer disease.