One prior study reported a nominal association between rs3778150 and heroin dependence. Using a subset of the Australian Heroin Dependence Study reported here (N=1,459 cases and 531 general population controls), Nelson et al. found that rs3778150 was associated with DSM-IV defined heroin dependence at P=0.024, but this finding did not pass multiple testing correction in that study (10). The rs3778150 association signal was greatly strengthened with the larger sample size in this study: P=1.7×10−4 in the Australian Heroin Dependence Study (N=5,120) and meta-analysis P=4.3×10−8 across all cohorts (total N=16,729). Beyond rs3778150, six other OPRM1 intron 1 SNPs have been reported for their associations with heroin or other opioid addiction phenotypes. Levran et al. reported that rs510769 and rs3778151 were nominally associated in 596 European American severe heroin addicts and healthy controls, but these findings did not surpass multiple testing correction (12). Zhang et al. found that rs524731, rs511435, rs3823010, and rs495491 were nominally to significantly associated in 429 European American DSM-defined opioid dependent cases and controls (19), who were ascertained in parallel to the African Americans from the CIDR –
