MAPT and Cognitive impairment: Interestingly, increases in exogenous cholesterol can mimic this scenario, resulting in APP internalization and elevations in C99 (Marquer et al, 2011), increases in the Aβ42:40 ratio (Marquer et al, 2014), Tau phosphorylation (van der Kant et al, 2019), and hippocampal atrophy and cognitive impairment (Djelti et al, 2015).