The brain-derived neurotrophic factor gene as a possible susceptibility candidate for Alzheimer's disease in a chinese population.

Brain-derived neurotrophic factor (BDNF), a member of the neurotrophic factor family, may represent a candidate gene conferring susceptibility to Alzheimer's disease (AD). This is because it has an important role in neuronal survival, and a decreased central level of BDNF is observed in AD. Some previous studies, though not all, have demonstrated that BDNF C270T polymorphisms might be associated with AD susceptibility. We examined the association of the C270T polymorphisms with sporadic AD in a Chinese cohort of 175 AD patients and 189 controls. We also tested BDNF Val66Met-C270T haplotypes for an interaction with the apolipoprotein E upsilon4 (APOE4) allele in AD. The results showed that the frequency of the 66Val allele was significantly lower in AD than controls (p = 0.031), but no significant difference in C270T allele or genotype frequencies was observed between AD cases and controls. Global case-control haplotype analysis showed that there is significant difference in haplotype distribution between both groups (p = 0.033). Stratification of the data according to the APOE status showed that in APOE4 allele bearers there was no significant difference in the frequency of haplotype 66Val-270C between AD and controls (p = 0.125), although there was a significant difference between the two groups in non-APOE4 carriers (p = 0.002). These results suggest that BDNF genetic variation may possibly affect the risk for AD, particularly in subjects who are negative for APOE4.