Brain Monoamine Oxidase A Activity Predicts Trait Aggression

Medical Department, Brookhaven National Laboratory, Upton, New York 11973, USA.
The Journal of Neuroscience : The Official Journal of the Society for Neuroscience (Impact Factor: 6.34). 06/2008; 28(19):5099-104. DOI: 10.1523/JNEUROSCI.0925-08.2008
Source: PubMed


The genetic deletion of monoamine oxidase A (MAO A), an enzyme that breaks down the monoamine neurotransmitters norepinephrine, serotonin, and dopamine, produces aggressive phenotypes across species. Therefore, a common polymorphism in the MAO A gene (MAOA, Mendelian Inheritance in Men database number 309850, referred to as high or low based on transcription in non-neuronal cells) has been investigated in a number of externalizing behavioral and clinical phenotypes. These studies provide evidence linking the low MAOA genotype and violent behavior but only through interaction with severe environmental stressors during childhood. Here, we hypothesized that in healthy adult males the gene product of MAO A in the brain, rather than the gene per se, would be associated with regulating the concentration of brain amines involved in trait aggression. Brain MAO A activity was measured in vivo in healthy nonsmoking men with positron emission tomography using a radioligand specific for MAO A (clorgyline labeled with carbon 11). Trait aggression was measured with the multidimensional personality questionnaire (MPQ). Here we report for the first time that brain MAO A correlates inversely with the MPQ trait measure of aggression (but not with other personality traits) such that the lower the MAO A activity in cortical and subcortical brain regions, the higher the self-reported aggression (in both MAOA genotype groups) contributing to more than one-third of the variability. Because trait aggression is a measure used to predict antisocial behavior, these results underscore the relevance of MAO A as a neurochemical substrate of aberrant aggression.

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    • "Human genomes contain VNTRs within the 5= untranslated region (UTR) of the monoamine oxidase A (MAOA) gene, which are 30 bp in length with tandem repeats of three, four, or five (Sabol et al. 1998). Expression of the MAOA gene is related to aggressive character and behavior (Lawson et al. 2003; Newman et al. 2005; Wendland et al. 2006b; Alia-Klein et al. 2008), and the MAOA VNTR polymorphism in the 5= UTR region affects its transcription (Deckert et al. 1999). Connection studies between MAOA VNTR polymorphisms and the transcriptional regulation of the MAOA gene have been reported in humans (Beach et al. 2010; Guo et al. 2008; Pai et al. 2007). "
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    ABSTRACT: Variable number of tandem repeats (VNTRs) are scattered throughout the primate genome, and genetic variation of these VNTRs have been accumulated during primate radiation. Here, we analyzed VNTRs upstream of the monoamine oxidase A (MAOA) gene in 11 different gibbon species. An abundance of truncated VNTR sequences and copy number differences were observed compared to those of human VNTR sequences. To better understand the biological role of these VNTRs, a luciferase activity assay was conducted and results indicated that selected VNTR sequences of the MAOA gene from human and three different gibbon species (Hylobates klossii, Hylobates lar, and Nomascus concolor) showed silencing ability. Together, these data could be useful for understanding the evolutionary history and functional significance of MAOA VNTR sequences in gibbon species.
    Genome 10/2014; 57(8):1-6. DOI:10.1139/gen-2014-0065 · 1.42 Impact Factor
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    • "Alia-Klein et al72 confirmed the functional relevance of the MAOA enzyme by showing moderate negative correlations of brain MAOA activity with trait aggression. However, no differences in enzymatic activity were found regarding genotype, in line with other research failing to find such relationship.73 "
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    ABSTRACT: Hereditary factors are increasingly attracting the interest of behavioral scientists and practitioners. Our aim in the present article is to introduce some state-of-the-art topics in behavioral genetics, as well as selected findings in the field, in order to illustrate how genetic makeup can modulate the impact of environmental factors. We focus on the most-studied polymorphism to date for antisocial responses to adversity: the monoamine oxidase A gene. Advances, caveats, and promises of current research are reviewed. We also discuss implications for the use of genetic information in applied settings.
    Psychology Research and Behavior Management 07/2014; 7:185-200. DOI:10.2147/PRBM.S40458
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    • "MAOB activity was significantly reduced in G allele than in A allele carrying males (P = 0.027). The G allele had been associated with lower MAOB activity in human brain [38]. In contrast, Garpenstrand et al. [39] found that individuals with the “A-allele” displayed significantly lower platelets enzyme activity than individuals with the “G-allele.” "
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    ABSTRACT: Autism is a neurodevelopmental disorder with indisputable evidence for a genetic component. This work studied the association of autism with genetic variations in neurotransmitter-related genes, including MAOA uVNTR, MAOB rs1799836, and DRD2 TaqI A in 53 autistic patients and 30 healthy individuals. The study also analyzed sequence variations of miR-431 and miR-21. MAOA uVNTR was genotyped by PCR, MAOB and DRD2 polymorphisms were analyzed by PCR-based RFLP, and miR-431 and miR-21 were sequenced. Low expressing allele of MAOA uVNTR was frequently higher in female patients compared to that in controls (OR = 2.25). MAOB G allele frequency was more significantly increased in autistic patients than in controls (P < 0.001 for both males and females). DRD2 A1+ genotype increased autism risk (OR = 5.1). Severity of autism tends to be slightly affected by MAOA/B genotype. Plasma MAOB activity was significantly reduced in G than in A allele carrying males. There was no significant difference in patients and maternal plasma MAOA/B activity compared to controls. Neither mutations nor SNPs in miR-431 and miR-21 were found among studied patients. This study threw light on some neurotransmitter-related genes suggesting their potential role in Autism pathogenesis that warrants further studies and much consideration.
    The Scientific World Journal 12/2013; 2013(3):670621. DOI:10.1155/2013/670621 · 1.73 Impact Factor
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