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Background/aims: In the present study, we examined whether DNA methylation of the brain-derived neurotrophic factor (BDNF) promoter is associated with the manifestation and clinical presentation of Alzheimer's disease (AD)., Methods: Of 20 patients with AD and 20 age-matched normal controls (NCs), the DNA methylation of the BDNF promoter (measured using peripheral blood samples) was completely analyzed in 12 patients with AD and 6 NCs. The resulting methylation levels were compared statistically. Next, we investigated the correlation between the DNA methylation levels and the clinical presentation of AD., Results: The total methylation ratio (in %) of the 20 CpG sites was significantly higher in the AD patients (5.08 ± 5.52%) than in the NCs (2.09 ± 0.81%; p < 0.05). Of the 20 CpG sites, the methylation level at the CpG4 site was significantly higher in the AD subjects than in the NCs (p < 0.05). Moreover, the methylation level was significantly and negatively correlated with some neuropsychological test subscores (registration, recall, and prehension behavior scores; p < 0.05)., Conclusion: These results suggest that the DNA methylation of the BDNF promoter may significantly influence the manifestation of AD and might be associated with its neurocognitive presentation.

Background: Some polymorphisms of the neurotrophin family have previously been investigated as candidate genes for Alzheimer's disease (AD). In the present study, we examined whether neurotrophin-3 (NTF-3) polymorphisms are genetic risk factors in patients with AD., Methods: From a sample of 507 subjects, we recruited 248 age-matched subjects divided into 2 groups: AD patients (n = 143) and normal controls (NCs) (n = 105). We identified 3 representative NTF-3 single nucleotide polymorphisms (SNPs): rs6332, rs6489630, and rs4930767. Next, we statistically compared the allele frequencies of each SNP between the AD and NC groups in the early-onset (<65 years) cases under a more limited age-matched condition., Results: We found a significant association between rs6332 and the total group of AD patients (p = 0.013) and significant associations between both rs6332 (p = 0.033) and rs6489630 (p = 0.035) and early-onset AD patients., Conclusion: These results suggest that NTF-3 SNPs may not only be associated with AD itself, but also with early-onset AD in Japanese patients, assuming that the NTF-3 gene may have age-related effects on neurodegenerative diseases.

Background: We investigated whether neurotrophin (NT)-3 polymorphisms influenced the executive function of patients with 2 separate disease stages with similar dementia conditions: amnestic mild cognitive impairment (A-MCI) or mild Alzheimer disease (AD)., Methods: Among 215 outpatients with dementia and MCI, 155 with mild AD (n = 108) or A-MCI (n = 47) were recruited and divided into three genotypic groups based on the representative NT-3 functional polymorphisms rs6332 and rs6489630. Next, we compared the frontal assessment battery (FAB) total and subtest scores between the three genotypic groups., Results: The total FAB score was not significantly associated with the rs6332 and rs6489630 genotypes; however, the conflicting instructions score among the 6 subtests was significantly associated with the rs6332 genotype (p < 0.05). Moreover, in patients with mild AD, the conflicting instructions score differed significantly among the three genotypic groups of rs6332 (p < 0.05) (G/G < A/A: p = 0.042 and G/A < A/A: p = 0.041). No significant differences in any other demographic variables were observed among the three genotypes of rs6332 and rs6489630., Conclusion: These results suggested that an NT-3 polymorphism, rs6332, may significantly influence executive function, reflecting interference performances among patients with mild-stage AD., (Copyright © 2012 S. Karger AG, Basel.)

Background/aims: To address the clinical neurocognitive roles of nerve growth factor (NGF) genetic polymorphism in early-stage Alzheimer's disease (AD) and amnestic mild cognitive impairment (A-MCI), we investigated the association between this single-nucleotide polymorphism (SNP) and executive dysfunction as a nonmemory cognitive impairment., Methods: Among 200 outpatients with dementia and MCI whose NGF SNP rs6330 genotype was identified, those with A-MCI (n = 35) and early-stage AD (n = 67) were recruited and divided into three groups according to genotype (C/C: n = 58, C/T: n = 39, T/T: n = 5). Then, the Frontal Assessment Battery (FAB) scores were compared among the three (C/C, C/T, T/T) or two (C/C, T carrier) genotype groups., Results: Among the subtests, a significant difference was only noted for the go/no-go scores (p < 0.01) between C/C and T carriers. However, no significant differences in the demographic variables and other neuropsychological subtest scores reflecting attentional and memory function were observed among the genotypes., Conclusion: Regarding the functional roles of neurotrophin polymorphisms as they relate to executive dysfunction, the NGF gene rs6330 might influence the inhibition task in Japanese patients with early-stage AD or A-MCI., (Copyright © 2012 S. Karger AG, Basel.)