In this study of a genome-wide analysis of a general population sample using a quantitative AD factor score, none of the SNP results achieved genome-wide significance. The genes that showed more tentative signals encoded kinases, peptidases, binding proteins, zinc finger proteins, and channel proteins. Our permutation tests in the EA sample produced statistical significance for a number of genes, with three of them (PITRM1, PIGG and AKAP9) demonstrating experiment-wide significance. Amongst these top genes, PITRM1 (p=0.0004) encodes a protein involved in the degradation of peptides. Although PITRM1 may at first appear to have little relevance to AD, a prior genome-wide study found 3 SNPs in this gene showing p<8.9×10-6 (Anney et al. 2008) impacting on risk for conduct disorder which has been frequently shown to increase vulnerability to alcohol problems.
