This review tries to cover the literature on the impact of gene variants implicated in psychiatric disorders on serotonin, dopamine, and MAO-A radioligand binding in living humans.
Collectively, we confirmed that MAOA is a risk gene for psychiatric disorders, and our results provide useful information toward a better understanding of genetic mechanism involving MAOA underlying risk of complex psychiatric disorders.
Further studies are required to better understand the association of symptomatology of schizophrenia and other psychiatric disorders with COMT gene polymorphism.
Although a polymorphism in this gene, COMTVal(158)Met, affects human behavior in response to stress little is known about its effect on dopaminergic activity associated with the human stress response, which may be of interest for stress-related psychiatric disorders such as psychosis.
This study examined the association of COMT with salivary cortisol across a 1-year period in healthy and at-risk adolescents with Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision Axis II diagnoses.
In women, low expression of MAOA (MAOA-L) was related significantly to greater happiness (0.261 SD increase with one L-allele, 0.522 SD with two L-alleles, P=0.002) after adjusting for the potential effects of age, education, household income, marital status, employment status, mental disorder, physical health, relationship quality, religiosity, abuse history, recent negative life events and self-esteem use in linear regression models.
However, MAO-A inhibitors, which directly acts on MAO-A protein, have limited use due to their adverse effects. microRNAs (miRNAs) are 18-22 nucleotide long, small non-coding RNAs, which have recently emerged as regulators of protein levels that could potentially be new therapeutic targets for psychiatric disorders.
A variation in catechol-O-methyltransferase (COMT) gene (Val(108/158)Met) affects the physiological response of hippocampal-prefrontal circuits, predicts variation in human memory and is associated with increased risk for psychiatric disorders.
Increasing evidence suggests that the catechol-O-methyltransferase (COMT) gene might be associated with cognition in patients with mental disorders and healthy people.
We then examined genetic polymorphisms in four candidate genes (DRD4, DAT, COMT and MAOA) that have been shown to contribute to the risk of developing various psychiatric disorders where attention is disrupted.
The present study appears to be the first comprehensive meta-analysis of COMT genetic association studies to cover all psychiatric disorders for which there were available data, published in any language, and with an emphasis on investigating disorder subtypes (defined clinically or by demographic or other variables).
Monoamine oxidase A (MAO-A) plays an important role in various functions of the brain, such as regulation of mood, anxiety and aggression, and dysregulation of MAO-A is observed in stress-related psychiatric disorders.
By conferring allele-specific transcriptional activity on the monoamine oxidase A (MAOA) gene in humans, length variation of a repetitive sequence [(variable number of tandem repeat (VNTR)] in the MAOA promoter influences a constellation of personality traits related to aggressive and antisocial behavior and increases the risk of neurodevelopmental and psychiatric disorders.
To investigate the possible influence of the allelic variants of the MAOA gene-linked polymorphic region (MAOA-LPR) on the genetic predisposition to psychiatric disorders, we have performed a case-control association study.
Specifically, the Val<sup>158</sup>Met polymorphism greatly alters COMT function and cognitive performance in both psychiatric disorders and healthy controls.
The catechol-O-methyltransferase (COMT) gene contains a functional polymorphism, Val158Met which has been related to common diseases like cancer, psychiatric illness and myocardial infarction.
Many association studies have reported associations between the catechol-O-methyltransferase (COMT) gene and psychiatric disorders including major depression (MDD).
Many clinical and genomic association studies suggested that the catechol-O-methyltransferase (COMT) gene region was an important genetic locus for psychiatric disorders, because of the proposed relationship between its function in catecholaminergic neurotransmission and individual response to antidepressants, and vulnerability to psychiatric disorders.
The identification of candidate genes for heart anomalies, mental illness, and other clinical phenotypes has been reported in the past year with a focus on TBX1 for cardiac and craniofacial phenotypes and COMT and PRODH for psychiatric disorders.