For that particular purpose, we chose to analyze the effects of a genetic risk score based on the number of ApoE4 alleles, i.e. 0, 1, or 2, a well known and established risk factor for development of AD and corresponding signs of atrophy in MRI (Vemuri et al., 2010a; Risacher et al., 2010; Morgen et al., 2013; Taylor et al., 2014; Tosun et al., 2010; Moffat et al., 2000; Hostage et al., 2014). Here, APOE is linked to Alzheimer disease.