APP and Down syndrome: Down syndrome (DS) is the most common chromosomal aberration worldwide (Fortea et al., 2021) caused by the triplication of chromosome 21 which harbors the amyloid precursor protein gene (APP; Doran et al., 2017), resulting in an increased gene dosage causing APP overexpression and consequently the accumulation of beta-amyloid in the central nervous system (Oyama et al., 2008).