In addition to its known association with cognitive decline and Alzheimer's, including recent GWAS studies identifying ApoE ε4 as the main genetic determinant of Alzheimer's, polymorphic forms of ApoE ε4 have been linked to diverse physiological consequences including atherosclerosis, faster disease progression in multiple sclerosis, poor outcomes in traumatic brain injury, sleep apnea and a higher risk for type III hyperlipoproteinemia (Breslow et al., 1982; Elias-Sonnenschein et al., 2011; Feussner et al., 1998; Friedman et al., 1999; Kadotani et al., 2001; Schmidt et al., 2002). Here, APOE is linked to sleep apnea syndrome.