Association between BDNF Polymorphism (Val66Met) and Executive Function in Patients with Amnestic Mild Cognitive Impairment or Mild Alzheimer Disease.

Background: In the present study, we examined whether brain-derived neurotrophic factor (BDNF) polymorphism (Val66Met) influenced the changeable executive dysfunction of patients with two separate disease stages: amnestic mild cognitive impairment (A-MCI) or mild Alzheimer disease (AD), which are comparatively similar demented conditions. Methods: Among 200 outpatients with dementia and MCI, 146 outpatients with mild AD or A-MCI were recruited and divided into two genotypic groups, valine homozygosity (Val/Val) and methionine (Met) carriers, based on the representative BDNF functional polymorphism Val66Met. Next, we compared the Frontal Assessment Battery (FAB) total and subtest scores between the two genotypic groups according to each of two different disease stages: A-MCI (n = 42) and mild AD (n = 104). Results: Among patients with only a mild stage of AD, the FAB total and go/no-go scores were significantly lower (p < 0.05) among the subjects with the Val/Val genotype than among the Met carriers. However, no significant differences in any other demographic variables were observed between the genotypes according to each of different disease stages. A significant interaction between Val66Met and age was not observed for the FAB scores. Conclusion: These results suggested thatthe BDNF gene may significantly influence executive dysfunction, including inhibition tasks, among patients with mild-stage AD. Copyright © 2012 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]