Association between heroin dependence and prodynorphin gene polymorphisms

► PDYN 68bp VNTR was found to be associated with heroin dependence. ► Significantly more TCT haplotypes (rs1022563, rs2235749, rs910080 in 3′UTR) were found in heroin-dependent patients than in the controls. ► We found significant pointwise correlation of these three variants (rs1022563, rs2235749 and rs910080) with heroin dependence. ► These findings support the important role of PDYN polymorphism in heroin dependence.