The brain-derived neurotrophic factor Val66Met polymorphism is associated with reduced hippocampus perfusion in
Barbara Borroni1, Marta Bianchi, Enrico Premi
1The Centre for Ageing Brain and Neurodegenerative Disorders, Neurology Unit, University of Brescia, Brescia, Italy. bborroni@inwind.it
Abstract:
Brain-derived neurotrophic factor (BDNF) promotes several functions in neurons and modulates neurotransmissions, especially in hippocampal regions. Frontotemporal lobar degeneration (FTLD) has a strong genetic background, but genetic risk factors associated with sporadic disease are unknown. Hippocampal involvement is frequently observed in FTLD. The aims of this study were: i) to evaluate if BDNF genetic variations are associated with an increased risk of developing FTLD; and ii) to assess the neuroimaging profiles associated with BDNF polymorphisms. Ninety-one FTLD patients who underwent SPECT imaging and blood sampling entered the study, and clinical, cognitive, and behavioral examinations were performed. A larger group of FTLD patients (n = 194) and controls (n = 396; 162 healthy subjects and 234 Alzheimer's disease (AD) patients) underwent genetic analyses, considering BDNF polymorphisms (Val66Met, rs2049045 C/G, G11757C). A significant different distribution of G11757C genotype in FTLD (GG 53.1%, GC 42.8%, CC 4.1%) compared to controls (G/G 55.6%, G/C 34.6%, C/C 9.8%, p = 0.020) was found. No other significant differences in genotype and allele distributions were detected. The effect of BDNF polymorphisms on brain perfusion was analyzed. BDNF Val66Met A* carriers (A/A or G/A) showed a significant greater hypoperfusion parahippocampal regions as compared to G/G carriers (p < 0.005). No effect of G11757C polymorphism on brain perfusion was found. rs2049045 C/G was not considered as in linkage disequilibrium with Val66Met polymorphism. BDNF Val66Met polymorphism may play a role as a modulator of the FTLD expression and may drive a selective damage in specific brain region affected by the disease.
