Article

The brain-derived neurotrophic factor (Val66Met) polymorphism and depression in Mexican-Americans

Department of Psychiatry & Behavioral Sciences, Center on Pharmacogenomics, University of Miami Miller School of Medicine, Miami, Florida 33136-1013, USA.
Neuroreport (Impact Factor: 1.64). 09/2007; 18(12):1291-3. DOI: 10.1097/WNR.0b013e328273bcb0
Source: PubMed

ABSTRACT The hypothesis that brain-derived neurotrophic factor (BDNF) is involved in the pathogenesis of major depression is supported by several research findings; however, genetic studies assessing the relationship between BDNF and psychiatric disorders have produced conflicting results. We examined the effect of a BDNF polymorphism on depression susceptibility in Mexican-Americans. The single nucleotide polymorphism (Val66Met), which has been shown to have functional and behavioral effects, was genotyped in 284 depressed participants and 331 controls, showing association with depression (P=0.005). Individuals homozygous for the major allele (GG) had an increased chance of being depressed (OR=1.7 95% CI 1.17-2.47). Our findings support the association of BDNF single nucleotide polymorphism rs6265 and depression, suggesting that this polymorphism may increase susceptibility to major depression in Mexican-Americans.

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    • "Depression and poor mental health have been long identified to be closely linked and are risk factors to alcohol abuse (Davidson, 1995; Weitzman, 2004; Briere et al., 2014). BDNF variants have also been studied for association with depressive disorders and evidence of association has been found (Ribeiro et al., 2007; Lavebratt et al., 2010; Suchanek et al., 2011; Pei et al., 2012; Rippey et al., 2013 "
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    ABSTRACT: Aims: The functional BDNF single nucleotide polymorphism (SNP) rs6265 has been associated with many disorders including schizophrenia and alcohol dependence. However, studies have been inconsistent, reporting both positive and negative associations. Comorbid alcohol dependence has a high prevalence in schizophrenia so we investigated the role of rs6265 in alcohol dependence in Australian populations of schizophrenia and alcohol-dependent patients. Methods: Two BDNF SNPs rs6265 and a nearby SNP rs7103411 were genotyped in a total of 848 individuals. These included a schizophrenia group (n = 157) and a second schizophrenia replication group (n = 235), an alcohol-dependent group (n = 231) that had no schizophrenia diagnosis and a group of healthy controls (n = 225). Results: Allelic association between rs7103411 and comorbid alcohol dependence was identified (P = 0.044) in the primary schizophrenia sample. In the replication study, we were able to detect allelic associations between both BDNF SNPs and comorbid alcohol dependence (rs6265, P = 0.006; rs7103411, P = 0.014). Moreover, we detected association between both SNPs and risk-taking behaviour after drinking (rs6265, P = 0.005; rs7103411, P = 0.009) and we detected strong association between both SNPs and alcohol dependence in males (rs6265, P = 0.009; rs7103411, P = 0.013) while females showed association with multiple behavioural measures reflecting repetitive alcohol consumption. Haplotype analysis revealed the rs6265-rs7103411 A/C haplotype is associated with comorbid alcohol dependence (P = 0.002). When these SNPs were tested in the non-schizophrenia alcohol-dependent group we were unable to detect association. Conclusion: We conclude that these BDNF SNPs play a role in development of comorbid alcohol dependence in schizophrenia while our data do not indicate that they play a role in alcohol-dependent patients who do not have schizophrenia.
    Alcohol and Alcoholism 07/2014; 49(5):491-497. DOI:10.1093/alcalc/agu040 · 2.09 Impact Factor
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    • "In most cases, this psychological mechanism could keep these individuals with the Met allele in a positive emotional state. This result further indicated that the Met allele plays a protective role in certain neurological conditions for its roles in disengagement for positive stimuli (Lang et al. 2005, Neves-Pereira et al. 2005, Kremeyer et al. 2006, Ribeiro et al. 2007). "
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    ABSTRACT: Studies have indicated that a functional polymorphism (Val66Met) in a brain-derived neurotrophic factor (BDNF) gene can influences human cognitive functions and mood disorders. In this study, we examined associations of BDNF Val66Met with attentional bias and personality in an unaffected population. The results showed that BDNF Val66Met was significantly associated with attentional disengagement for positive cueing words in extraverts. Moreover, there was a positive correlation between the dosages of Met allele and attentional disengagement, however, we did not observe any significant influences of BDNF Val66Met on personality traits. These preliminary results indicate that the individual differences in attentional bias for positive words are partially underpinned by BDNF.
    Acta neurobiologiae experimentalis 01/2013; 73(2):280-8. · 2.24 Impact Factor
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    • "Another important limitation of BDNF as a biomarker of AD is the fact that it is also altered in a series of neuropsychiatric conditions (Teixeira et al. 2010). For instance, the Val66Met polymorphism in the BDNF gene has been consistently associated with major depression (Hwang et al. 2006; Ribeiro et al. 2007; Taylor et al. 2007). Patients with major depression and bipolar disorder (either in manic or in depressive states) show significantly reduced serum levels of BDNF in comparison with controls (Machado- Vieira et al. 2007; Cunha et al. 2006; Diniz et al. 2010a, b). "
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    ABSTRACT: Brain-derived neurotrophic factor (BDNF) is the most widely distributed neurotrophin in the central nervous system where it plays several pivotal roles in synaptic plasticity and neuronal survival. As a consequence, BDNF became a key target in the physiopathology of several neurological and psychiatric diseases. Recent studies have reported altered levels of BDNF in the circulation, i.e. serum or plasma, of patients with Alzheimer's disease (AD), and low BDNF levels in the CSF as predictor of future cognitive decline in healthy older subjects. Altered BDNF circulating levels have also been reported in other neurodegenerative and psychiatric disorders, hampering its use as a specific biomarker for AD. Therefore, BDNF seems to be an unspecific biomarker of neuropsychiatric disorders marked by neurodegenerative changes.
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