Several studies analyzed other SNPs in the OPRM1 gene for association with addiction. An association with substance dependence (SD) (heroin, cocaine and alcohol) was shown with three promoter SNPs (-1793T>A, -1699insT and -2044C>A) (Hoehe et al. 2000; Luo et al. 2003). SNP rs1074287, located in the 5′ upstream region (-11.6 kb from exon 1) was found to be associated with heroin addiction in EA subjects (Nielsen et al. 2008).
