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Val66Met Polymorphism (val66met + polymorphism)

Distribution by Scientific Domains

Medical Sciences	57%
Life Sciences	42%

Selected Abstracts

Additive effect of BDNF and REST polymorphisms is associated with improved general cognitive ability

GENES, BRAIN AND BEHAVIOR, Issue 7 2008
F. Miyajima
Brain-derived neurotrophic factor (BDNF) is a pleiotropic protein involved in neuronal proliferation, differentiation, synaptic plasticity and survival. Independent studies investigating association between the functional BDNF Val66Met polymorphism and cognitive abilities have reported some conflicting findings, which may reflect inadequate sample size, variation in testing methods, population stratification or the confounding effects of other genes. To test the latter hypothesis, we screened and genotyped polymorphisms in the RE1-silencing transcription factor (REST) gene whose function includes the downregulation of BDNF expression. We identified an exon 4 hexadecapeptide variable number tandem repeat (VNTR) with either four or five copies that was located within a proline-rich domain and investigated a further five single nucleotide polymorphisms (SNPs). Using a cohort of 746 community-dwelling older volunteers, we analysed REST genotype data both independently and in combination with the BDNF Val66Met polymorphism. A haplotype within the REST gene containing the four copy VNTR and a non-synonymous SNP showed a weak but significant association with a higher score of general intelligence (P = 0.05). Analysis of this haplotype and the BDNF Val66Met polymorphism in combination showed a significant interaction (global P -value = 0.0003) with an additive increase in cognitive performance for those possessing the BDNF Val66 allele and the REST haplotype containing the four copy repeat (P = 0.004). The REST haplotypes in combination with the BDNF Met66 polymorphism did not reduce cognitive performance more than the independent influence of the Met66 allele. Our results suggest that investigation of a common REST polymorphism may be necessary to help reduce contrasting reports based around BDNF Val66Met and cognition. [source]

Effects of brain-derived neurotrophic factor Val66Met polymorphism on hippocampal volume change in schizophrenia

HIPPOCAMPUS, Issue 9 2010
P. Cédric M.P. Koolschijn
Abstract A functional polymorphism of the brain-derived neurotrophic factor (BDNF) gene (Val66Met) has been associated with the risk for schizophrenia and volume differences in the hippocampus. However, little is known about the association between progressive brain volume change in schizophrenia and BDNF genotype. The aim of this study was to investigate the relationship between hippocampal volume change in patients with schizophrenia and healthy control subjects and BDNF genotype. Two structural magnetic resonance imaging brain scans were acquired of 68 patients with schizophrenia and 83 healthy subjects with an interval of approximately 5 yrs. Hippocampal volume change was measured and related to BDNF genotype in patients and healthy controls. BDNF genotype was not associated with hippocampal volume change over time in patients or healthy controls, nor could we replicate earlier findings on smaller hippocampal volume in Met-carriers. However, we did find a genotype-by-diagnosis interaction at baseline demonstrating smaller hippocampal volumes in patients homozygous for the Val-allele relative to healthy Val-homozygotes. In addition, irrespective of genotype, patients showed smaller hippocampal volumes compared with healthy controls at baseline. In summary, our results suggest that the BDNF Val66Met polymorphism is not associated with hippocampal volume change over time. Nevertheless, our findings may support the possibility that BDNF affects brain morphology differently in schizophrenia patients and healthy subjects. © 2009 Wiley-Liss, Inc. [source]

Prefrontal cognition in schizophrenia and bipolar illness in relation to Val66Met polymorphism of the brain-derived neurotrophic factor gene

PSYCHIATRY AND CLINICAL NEUROSCIENCES, Issue 1 2006
JANUSZ K. RYBAKOWSKI md
Abstract, The measures of prefrontal cognition have been used as endophenotype in molecular-genetic studies. Brain-derived neurotrophic factor (BDNF) has been implicated in cognitive functions and in the pathogenesis of major psychoses. This study investigates the relationship between Val66Met polymorphisms of the BDNF gene and prefrontal cognitive function in 129 patients with schizophrenia and 111 patients with bipolar mood disorder. Cognitive tests included the Wisconsin Card Sorting Test (WCST), with such domains as number of perseverative errors, non-perseverative errors, completed corrected categories, conceptual level responses, and set to the first category, and the N-back test, where mean reaction time and percent of correct reactions were measured. Genotyping for Val66Met BDNF polymorphism was done by polymerase chain reaction method. In schizophrenia, no relationship between Val66Met polymorphism of the BDNF gene and the results of the WCST was observed. Patients with Val/Val genotype had a higher percentage of correct reactions in the N-back test than those with the remaining genotypes. Bipolar patients with Val/Val genotype obtained significantly better results on three of five domains of the WCST. No relationship between BDNF polymorphism and the results of the N-back test was found in this group. A limitation to the results could be variable psychopathological state and medication during cognitive testing and lack of Hardy,Weinberg equilibrium in schizophrenia group. Val66Met polymorphism of the BDNF gene may be associated with cognitive performance on the WCST in bipolar mood disorder but not in schizophrenia. An association of this polymorphism with performance on the N-back test in schizophrenia and not in bipolar illness may suggest that in schizophrenia, the BDNF system may be connected with early phases of information processing. [source]

Lack of association between BDNF Val66Met gene polymorphism and late-onset depression in a Chinese Han population

ACTA NEUROPSYCHIATRICA, Issue 4 2009
Jiayong You
Background: Val66Met polymorphism in the brain-derived neurotrophic factor (BDNF) gene has been suggested to be associated with major depressive disorder (MDD). There were a few reports of the relationship between the variant and late-onset depression (LOD) in Chinese Han population. Objective: To investigate the relationship among BDNF Val66Met gene variants, BDNF plasma level and LOD. Methods: Chinese Han patients with LOD (n = 99) and control subjects (n = 110) were assessed for BDNF Val66Met gene polymorphism. BDNF plasma level was tested only in LOD. Results: There were no significant differences in genotypes and allele frequencies between cases and controls (p = 0.744 and p = 0.845, respectively). Plasma BDNF level also did not show significant differences in three genotypes in LOD (p = 0.860). Conclusion: The Val66Met polymorphism in BDNF gene may not confer susceptibility to LOD in Chinese Han population. [source]