Association of the Val66Met polymorphism of the BDNF gene with primary cranial-cervical dystonia patients from South-west China

Abstract

Background: The etiology of primary dystonia remains unclear. Recent genetic studies suggest that the Val66Met polymorphism of the BDNF gene is a genetic modifier in cranial-cervical dystonia in Caucasians. However, the finding is not consistent.

Patients and methods: A total of 193 patients with primary cranial-cervical dystonia from the Department of Neurology, West China Hospital of Sichuan University was included. From the same region, 216 healthy individuals were recruited as a control group. The Val66Met SNP was identified by polymerase chain reaction-restriction fragment length polymorphism.

Results: In the present study, cervical dystonia (59.59%) was the most common type of primary cranial-cervical dystonia. No significant difference was found in the genotype and minor allele frequencies between all patients and controls, between cervical dystonia patients and controls, and between craniocervical dystonia patients and controls. However, significant differences were found in the genotype and minor allele frequencies of Val66Met SNP between blepharospasm (BSP) patients and controls (P=0.0080 and P=0.0042, respectively), and between BSP patients and patients with craniocervical derived from BSP (P=0.0010 and P=0.0002, respectively).

Conclusion: Minor allele "A" of BDNF Val66Met SNP may increase the risk for developing BSP and may be a protective factor for preventing BSP progressing to craniocervical dystonia. More association studies involving a larger number of participants are needed to confirm the present findings.

Keywords: BDNF gene; Primary dystonia; Vel66Met polymorphism.