The two-SNP haplotype associations with heroin addiction are presented in Table 3. Haplotypes carrying the non-risk rs1344706-C allele were collapsed, due to the low frequency of rs1344706-C/rs7597593-T (<1%) in both ancestry groups, and used as the reference. The haplotype carrying both risk alleles (rs1344706-A/rs7597593-T) was significantly associated with increased risk of heroin addiction in the European Americans-specific analysis (P=0.0064) and the multiancestry meta-analysis (P=0.0066), while the haplotype carrying rs1344706-A without rs7597593-T was not associated.
