Brain-derived neurotrophic factor (Val66Met) polymorphism and olfactory ability in young adults

Abstract

BackgroundBrain- derived neurotrophic factor (BDNF) is linked to neurodegenerative diseases (e.g. Alzheimer disease and Parkinson disease) which are often characterized by olfactory impairment. A specific single nucleotide polymorphism of the BDNF gene, the Val66Met, modulates intracellular trafficking and activity-dependent secretion of BDNF protein. The aim of this study was to investigate a possible association between brain- derived neurotrophic factor Val66Met polymorphism and olfactory function, a well-known biomarker for neurodegeneration, in healthy young adults. A total of 101 subjects (45 males, age 38.7 ± 9.4 years) were assessed using the Sniffin’ Sticks Extended Test, a highly reliable commercial olfactory test composed of three sub-parts, calculating olfactory threshold (sensitivity), odor discrimination and odor identification. The Val66Met polymorphism was determined by polymerase chain reaction -restriction fragment length polymorphism (PCR-RFLP) analysis.ResultsAn impaired function in Met carriers was found, especially when compared to subjects with Val/Val genotype, in the threshold (5.5 ± 2.0 vs 6.5 ± 1.8, p = 0.009), discrimination (10.3± 2.5 vs 11.9 ± 2.2, p = 0.002), and identification task (13.3 ± 1.6 vs 14.1 ± 1.3, p = 0.007), as well as in the overall TDI Score (29.1 ± 4.5 vs 32.6 ± 3.9, p < 0.001).ConclusionsThese findings appear to have implications for the evaluation of olfactory function and the relation of its impairment to cognitive decline and neurodegenerative disease.

Impact of BDNF Val66Met polymorphism on olfactory functions of female concussed athletes

“…Interestingly, executive as well as olfactory functions are both mediated by BDNF neurotrophins secreted over frontal brain areas, a region particularly vulnerable to concussions. In this study, better olfactory function performance specific to BDNF Met concussed athletes is at odds with previous uninjured animal models and healthy participants that rather linked the BDNF Met variant with diminished olfactory functioning [43,50]. As suggested by Barbey et al [41], the functional effect of the BDNF Met allele may differ under normal and pathological conditions.…”

“…A study by Hedner et al [49] revealed no effect of the BDNF Val66Met polymorphism on olfactory function in healthy young adults, whereas healthy older adults carrying the wild-type BDNF Val66Val (BDNF Val ) genotype and not the expected sub-group of BDNF Met carriers exhibited significantly reduced olfactory function. Another study conducted in young healthy adults using the Sniffin' Sticks Inventory Test (SSIT), a standardized battery of olfactory function tests with improved psychophysical properties, showed that carrying the BDNF Met genotype significantly reduced olfactory function [50]. The use of the SSIT allows a more detailed evaluation of olfactory functions, when compared to more traditional scratch-and-sniff tests, by looking at olfactory threshold, discrimination and identification for a better characterization of the deficits observed.…”

Do Environmental Factors (Practice and Feedback) Moderate the Effect of the Val66met BDNF Polymorphism on Motor Learning?

“…Checking of analysis sorted participants to three genetic categories: val/val (46 people), val/met (40 people), and met/met (14 people). The genotype's distribution of Val66Met polymorphism observed in both val/val and val/ met genotype satisfied the Hardy-Weinberg Equilibrium and were comparable with that previously observed in previous studies [17][18][19] . The experiment leader in this study was blinded for the genotype of the participants.…”

Association Between Atopic Dermatitis and Autism Spectrum Disorders: A Systematic Review

“…A more relevant common gene to AD and ASD is the brain-derived neurotrophic factor (BDNF) gene, which plays an important role in neurogenesis, cortical lamination, synaptic plasticity, and neuron survival [82,83]. Several studies, directly or indirectly, suggest an involvement of BDNF in ASD, usually showing that BDNF levels in the blood, serum and brain are increased in children with ASD compared with TD children [84].…”