Brain-derived neurotrophic factor polymorphism Val66Met influences cognitive abilities in the elderly.

Area of Science:

• Neuroscience
• Genetics
• Cognitive Psychology

Background:

• The brain-derived neurotrophic factor (BDNF) Val66Met gene polymorphism affects activity-dependent secretion and influences cognitive function.
• Previous research suggests the Met allele impairs long-term memory and hippocampal function, but some studies indicate protective roles in specific conditions or improved non-verbal reasoning in the elderly.

Purpose of the Study:

• To investigate the association between six haplotype-tagging single nucleotide polymorphisms (SNPs), including Val66Met, and cognitive performance in elderly individuals.
• To determine if the Met allele is associated with reduced cognitive functioning or offers a protective role in non-demented older adults.

Main Methods:

• Cognitive tests measuring fluid intelligence, processing speed, and memory were administered to 722 elderly individuals.
• Six haplotype-tagging SNPs were analyzed, with a focus on the Val66Met polymorphism.
• Magnetic resonance imaging (MRI) was used to assess hippocampal volume in a subgroup of 61 participants.

Main Results:

• The presence of the Met allele was associated with reduced cognitive performance across all tested domains.
• Nominal significance was observed for processing speed (P = 0.001), delayed recall (P = 0.037), and general intelligence (g) (P = 0.008).
• No significant associations were found for other SNPs after adjusting for Val66Met. Hippocampal volume showed a non-significant trend towards reduction in Met allele carriers.

Conclusions:

• The findings support previous research linking the Met allele of the BDNF gene to diminished cognitive functioning in older adults.
• No evidence was found for a protective role of the Met allele in non-demented elderly individuals.
• The study suggests potential structural brain changes, indicated by smaller hippocampal volumes, associated with the Met allele.