The brain-derived neurotrophic factor (BDNF) gene Val66Met polymorphism affects memory performance in older adults

Abstract

Objective: Memory impairment is an important contributor to the reduction in quality of life experienced by older adults, and genetic risk factors seem to contribute to variance in age-related cognitive decline. Brain-derived neurotrophic factor (BDNF) is an important nerve growth factor linked with development and neural plasticity. The Val66Met polymorphism in the BDNF gene has been associated with impaired episodic memory in adults, but whether this functional variant plays a role in cognitive aging remains unclear. The purpose of this study was to investigate the effects of the BDNF Val66Met polymorphism on memory performance in a sample of elderly adults. Methods: Eighty-seven subjects aged 4 55 years were recruited using a community-based convenience sampling strategy in Porto Alegre, Brazil. The logical memory subset of the Wechsler Memory Scale-Revised was used to assess immediate verbal recall (IVR), delayed verbal recall (DVR), and memory retention rate. Results: BDNF Met allele carriers had lower DVR scores (p = 0.004) and a decline in memory retention (p = 0.017) when compared to Val/Val homozygotes. However, we found no significant differences in IVR between the two groups (p = 0.088). Conclusion: These results support the hypothesis of the BDNF Val66Met polymorphism as a risk factor associated with cognitive impairment, corroborating previous findings in young and older adults.

BDNF Val66Met polymorphism and memory performance in older adults: the Met carrier effect is more complex than previously thought

“…Their conclusion was that, in a sample of elderly adults, BDNF Met allele carriers had impaired episodic memory performance as compared to Val/Val homozygotes. 1 However, conflicting evidence to this report exists, and the correlation between memory and Met allele carrier status is quite complex. One previous report focusing on older adults suggested that the BDNF Met allele is associated with higher memory performance, 2 whereas other studies found no effect of BDNF Val66Met variant on memory in older 3 or young adults.…”

“…The Val66Met polymorphism in the BDNF gene has been associated with a significant impact on episodic memory in adults. Azeredo et al 1 investigated effects of the BDNF Val66Met polymorphism on memory performance. Their conclusion was that, in a sample of elderly adults, BDNF Met allele carriers had impaired episodic memory performance as compared to Val/Val homozygotes.…”

Analyzing leukocyte telomere length in bipolar disorder: Authors’ reply

“…Another limitation of this study was the failure to exclude psychiatric patients. 1 The BDNF increase noted in the study by Zhang et al was demonstrated in patients with posttraumatic stress disorder, a condition known to have significant impact on memory.…”

“…We show, for the first time, that shorter leukocyte telomere length (LTL) is already present in individuals with the early stages of BD and is comparable to LTL from individuals in the late stages of the disease. 1 This result is at least surprising. We might speculate that, in BD, LTL would be proportional to disease duration.…”

“…[1][2][3][4] As these candidate gene studies have employed relatively small samples, it is difficult to interpret discrepant findings, which are the norm in genetic association research. By aggregating data across studies, meta-analyses provide a systematic method of evaluating such discrepant findings, as regarding the association between BDNF Val66Met polymorphism and memory function.…”