Four studies reported association of OPRK1 SNPs with alcohol dependence (AD); a study of a Taiwanese sample reported no association for SNPs rs1051660 and rs702764 (843A>G) (Loh el et al. 2004); in a study of 13 SNPs in 219 EA COGA families, an association of several SNPs in intron 2 was reported (Xuei et al. 2006). A third study of seven SNPs (not including SNPs from intron 2) in EA subjects reported an association of three SNPs (rs1051660, rs6985606 and rs997917) with AD or cocaine dependence (CD), and a seven-SNP haplotype with AD (Zhang et al. 2008). An association of the 830 bp indel (rs35566036) was reported in the COGA sample (Edenberg et al. 2008).
