BDNF rs6265 (Val66Met) Polymorphism as a Risk Factor for Blepharospasm.

A few genetic variants are implicated in the development of blepharospasm (BSP). The precise role of the rs6265 on the brain-derived neurotrophic factor (BDNF) gene on BSP remains controversial. The effect of rs6265 on BSP was evaluated. 206 patients with BSP and 206 healthy controls were recruited and genotyped for the rs6265. We also performed a meta-analysis, by pooling our results with those from previous studies. A significant effect of rs6265 on the risk of BSP was found in the dominant model of inheritance [odds ratio (OR) (95% confidence interval (CI) 1.52 (1.01-2.29), p = 0.044]. Mutational load analysis of rs6265 in the risk of BSP using the OR revealed that higher load of the "A" allele of rs6265 denotes higher probability of a subject to develop BSP (OR 1.48; 95% CI 1.00-2.19). Finally, pooled results from the meta-analysis revealed that the rs6265 is associated with an increased risk of BSP in the dominant model [OR 1.26; 95% CI 1.02-1.55, p = 0.03]. Also, higher load of the "A" allele of rs6265 denotes higher probability of a subject to develop BSP (OR 1.26; 95% CI 1.04-1.53). The present study provides additional evidence to the existing knowledge concerning the contribution of the rs6265 BDNF on the risk of developing BSP. While the pathophysiology and genetic susceptibility in BSP and focal dystonia are only partially understood, it seems that BDNF and rs6265 may constitute one essential risk factor that is heavily involved.