Do obsessive–compulsive disorder and Tourette syndrome share a common susceptibility gene? An association study of the BDNF Val66Met polymorphism in the Chinese Han population

Abstract

Objectives. We explored the association between the BDNF Val66Met polymorphism and susceptibility to both obsessive–compulsive disorder (OCD) and Tourette syndrome (TS) in the Chinese Han population. Methods. Genotyping for the BDNF Val66Met polymorphism was performed in 321 OCD patients and 426 healthy control subjects and case–control association study data were analysed. Additionally, we evaluated the genetic contribution of this variant in 331 TS patients (including 267 TS trios) and 519 controls using the transmission disequilibrium test (TDT) and case–control study. Results. A statistically significant difference was found in the genetic contribution of the BDNF Val66Met polymorphism between both the OCD (χ² = 7.50, P = 0.023 by genotype; χ² = 6.67, P = 0.01 by allele) and TS (χ² = 6.76, P = 0.03 by genotype; χ² = 4.27, P = 0.04 by allele), and control groups. TDT and GHRR analysis for TS trios also showed a significant transform disequilibrium of this polymorphism (TDT: χ² = 3.96, P = 0.05; HHRR: χ² = 4.33 P = 0.04; GHRR: χ² = 5.74, P = 0.02; χ² = 0.98, P = 0.37). There was also a significant gender trend between patients and controls in female cases for OCD and in male cases for TS. Conclusions. Our study supports the involvement of the BDNF Val66Met polymorphism as a common genetic susceptibility for OCD and TS in the Chinese Han population, showing specific gender trends.

Key words::

• BDNF
• obsessive–compulsive disorder
• Polymorphism
• Tourette syndrome
• common susceptibility

Acknowledgements

We thank all probands for their participation. This work was supported by the National Natural Science Foundation of China (81371499 and 30971586).

Statement of Interest

None to declare.