Two genotyped SNPs reached genome-wide significance (p<8.4 × 10−8). The most significant result was for a SNP on chromosome 13 in NALCN, (sodium leak channel, non-selective), rs17484734 (p=4.1 × 10−8, Figure 3A) for the probability of high-risk membership. This SNP also showed evidence of association with withdrawal (p=1.3 × 10−7). This SNP is in a recombination hot spot, and thus is not in linkage disequilibrium (LD) with the surrounding genotyped SNPs. There were no other genotyped SNPs in this region demonstrating association with these phenotypes. One imputed SNP, rs1151384, in moderate LD with rs17484734 (r2= 0.80) provided supporting evidence of association with both phenotypes (p≤1.4 × 10−6 for probability of high risk membership and withdrawal). No other imputed SNPs were in LD with these two SNPs (r2<0.20).
