OBJECTIVETo investigate the genetic association between brain-derived neurotrophic factor (BDNF) gene polymorphism and internalizing disorders, to provide the theoretical basis to explore the etiology of internalizing disorders.

METHODSPCR-based ligase detection reaction (PCR-LDR) was applied to tag single nucleotide lengh polymorphism (SNPs) of BDNF gene among 259 undergraduates affected by internalizing disorders and 269 healthy undergraduates. Haplotype analysis and multiple locus analysis were conducted to analyze the genotyping data.

RESULTSThe genotypic frequency of tag SNPs of BDNF gene did not deviate from Hardy-Weinberg equilibrium in both case and control groups. Rs12273539 was not associated with internalizing disorders (P > 0.05), but rs10835210 and rs2030324 were related to internalizing disorders (P < 0.05). The case group had more A allele of rs10835210 and C allele of rs2030324 when compared to the controls while A allele of rs10835210 and C allele of rs2030324 seemed to be the risk factors of internalizing disorder (OR = 1.877, P < 0.001; OR = 1.347, P < 0.05). Results of multiple locus analysis showed that the haplotype composed by the three tag SNPs which was related to internalizing disorders (chi(2) = 23.537, P < 0.001).

CONCLUSIONBDNF gene might serve as the susceptible gene for internalizing disorder.