Typical neuropathological hallmarks of Alzheimer’s disease (AD), including deposition of senile plaques containing amyloid beta‐peptide (Aβ), chronic oxidative stress, and neurofibrillary tangles composed of hyperphosphorylated tau protein are already present by the age of 40 years in DS persons (Lott, 2012). This evidence concerns the gene APP and Alzheimer disease.