MAPT and Alzheimer disease: Common underlying causes leading to these conditions can be attributed to abnormal accumulation of proteins such as amyloid in AD, misfolded proteins (typical for PolyQ diseases), aggregation of proteins such as Tau (AD and traumatic brain injuries), synuclein (PD) or TDP-43 (ALS), RNA toxicity, or translational products from repeats expansion within genes (Blokhuis et al., 2013; Hussain et al., 2018).