Using mutual information, we identified 58 plasma proteins in nonimpaired controls (Supplementary Table 4 and Extended Data Fig. 2a) that were associated with APOE genotype (Fig. 2b) and led to clustering based on the number of APOE ε4 alleles (Fig. 2c) rather than by neurodegenerative disease. The gene discussed is APOE; the disease is neurodegenerative disease.