APOE and early-onset autosomal dominant Alzheimer disease: For example, apoE plays a role in many brain disorders, including Alzheimer’s disease, mild cognitive impairment, multiple sclerosis, traumatic brain injury, Creutzfeldt-Jakob disease (CJD) and some others (Tamam et al. 2011; Ponsford et al. 2011; Amouyel et al. 1994).