Objective: To investigate the effect of brain-derived neurotrophic factor (BDNF) Val(66)Met polymorphism on the recovery after subcortical stroke, using the modified Rankin Scale (mRS).
Methods: Subcortical stroke patients with copies of BDNF Val(66)Met polymorphism (n=7) were compared to their controls (n=7) without a copy of BDNF Val(66)Met polymorphism after matching for initial severity, location and type of stroke. The mRS scores at 1 and 3 months after discharge from the neurorehabilitation unit were compared between the groups.
Results: A repeated measures ANOVA for mRS revealed significant interaction between time and group (F(2, 24) =37.2, p<0.001) and a significant effect of time (F(2, 24)=10.8, p<0.001), thereby reflecting significant differences between the Met allele (+) group and the Met allele (-) group. There was a significant difference in mRS scores at 3 months post-discharge between the two groups (p=0.01) although no difference was evident in mRS scores at 1 month post-discharge between the two groups. There were significant improvements between mRS scores on admission and mRS scores at 1 month post-discharge (p=0.02), and between mRS scores at 1 month post-discharge and mRS scores at 3 months post-discharge (p=0.004) in the Met allele (-) group.
Conclusion: BDNF Val(66)Met polymorphism may be associated with worse functional outcome in Korean patients with subcortical stroke. Therefore, BDNF Val(66)Met polymorphism should be considered as an important prognostic factor for recovery and responses to rehabilitation therapies after stroke in Korean patients. There is a need for developing different rehabilitation strategies for the population with BDNF Val(66)Met polymorphism. Further studies assessing different outcomes for various functional domains of stroke recovery are needed to clarify the role of BDNF Val(66)Met polymorphism.
Keywords: Brain plasticity; Brain-derived neurotrophic factor; Polymorphism; Recovery; Stroke.