Abnormal levels of C have been negatively associated with structural aspects of the hippocampus, related to the main features of AD pathogenesis such as β-amyloid deposition, tau hyperphosphorylation, and manifestations of synaptic deficits and cognitive impairment (Toledo et al., 2011; Notarianni, 2013; Wang et al., 2018; Ouanes and Popp, 2019). The gene discussed is MAPT; the disease is Alzheimer disease.