Because AD is pathologically characterized by extracellular aggregates of amyloid β (Aβ) peptides and intracellular neurofibrillary tangles containing phosphorylated tau20, we also examined whether ApoE deficiency resulted in Aβ and tau depositions in the SCN, retina and hippocampus, despite the young age of the mice. The gene discussed is APOE; the disease is Alzheimer disease.