SNP rs702543 in gene PDE4D, reported by Shifman [27] to be associated with neuroticism, was not present among our 1.7 M genotyped or imputed SNPs. However, we obtained p = 0.006 for association at the imputed SNP rs296410 that showed the highest R2 with rs702543 in the Hap Map CEU samples (R2 = 0.51); in our study, the major allele (T, frequency 0.52) at rs296410 shows a positive linear association with EPQ-N score. We could not replicate the association found by van den Oord [28] for the gene MAMDC1 on 14q. Three of the four SNPs they reported had a perfect proxy in our SNP set, but our lowest p-value in this gene was p = 0.43. We tested 3 genotyped SNPs in the gene NPY studied by Zhou30, including a SNP, rs16126, in high LD (R2≈0.9) with two of their reported SNPs, but we found p>0.4 at all three SNPs. Finally, we found no significant enrichment of a GO functional category among SNPs with p<10−4.
