Influence of brain-derived neurotrophic factor genetic polymorphisms on the ages of onset for heroin dependence in a Chinese population.

AIM The study aims at evaluating the association between brain-derived neurotrophic factor (BDNF) gene polymorphisms and heroin-dependent patients in the Chinese population. Three polymorphisms of the BDNF-gene (rs10835210, rs16917234, and rs6265) in 486 heroin-dependent patients and in 226 healthy controls were genotyped for analyzing the association of these polymorphisms with age of onset of heroin dependence. We defined the healthy cases as "unknown phenotype" and used the endophenotype (behavior traits) to stratify the heroin dependents group on the basis of self-reporting traits for examining the association between BDNF polymorphisms (rs10835210, rs16917234, and rs6265) and heroin dependence. RESULTS Allelic distributions of BDNF gene polymorphisms did not differ significantly between heroin-dependent patients and controls. However, we found that the AA carriers of BDNF rs6265 had an earlier onset of heroin dependence and a clearer tendency of family history of heroin-dependent than GG carriers after controlling behavior characteristics across rs6265 genotypes. CONCLUSIONS Our findings suggested that the BDNF genetic polymorphism (rs6265) may have effects on the age of onset of heroin dependence among the Chinese population. The BDNF gene could contribute to vulnerabilities to heroin dependence.