Relationship of the Met allele of the brain-derived neurotrophic factor Val66met polymorphism to memory after aneurysmal subarachnoid hemorrhage

OBJECTIVE: The brain-derived neurotrophic factor (BDNF) Va166Met polymorphism has been shown to be related to variability in episodic memory. We studied whether the Met allele is associated with poor learning and memory in survivors of aneurysmal subarachnoid hemorrhage (SAH). METHODS: Ninety-six patients were examined with a neuropsychological test battery approximately I year after SAH. Their deoxyribonucleic acid samples were genotyped for the BDNF Va166Met polymorphism. The Met carriers were compared to the Val/Val homozygous patients on the test performances. RESULTS: In the total sample, there was no difference between the genotype groups. However, among the patients with no cerebral infarction, the Met carriers had inferior learning and memory performance than the Val/Val homozygotes, but the groups did not differ on the nonmemory test performances. The patients with left and bilateral infarctions had deficits in verbal memory, which may have concealed the effect of the BDNF Val66Met polymorphism on memory in the total sample. CONCLUSION: As a whole, the BDNF Va166Met polymorphism was not associated with learning and memory performance in patients recovering from SAH. However, the Met allele might predict poor memory function among patients with SAH not complicated by a cerebral infarction. These findings support earlier reports of an association between the Met allele and low memory performance. Longitudinal studies comparing functional recovery from SAH between Met and Val/Val patients without cerebral infarctions are warranted.