These findings are consistent with epistatic effects of the COMT and MTHFR polymorphisms on prefrontal dopamine signaling, and suggest that in schizophrenia patients, the MTHFR 677T allele exacerbates prefrontal dopamine deficiency.
The COMT Val allele is associated with an increased risk of schizophrenia in subjects at increased familial risk, in whom it has demonstrable effects on prefrontal brain structure and function.
(3) The COMT genotype is related to performance on prefrontal cortex-dependent tasks and may contribute to the deficit in prefrontal-dependent memory processes in SPD as it does in schizophrenia.
We were able to detect statistical interaction between COMT and polymorphisms in candidate genes for schizophrenia, many of which had no significant main effect.
An attractive candidate gene for schizophrenia is the catechol-O-methyltransferase (COMT) gene, which is a modulator of dorsolateral prefrontal cortical function.
The authors tested for an association between a COMT haplotype and schizophrenia-spectrum disorders and for an eventual influence of a specific COMT genotype in the clinical outcome and in the response to treatment.
Findings suggest that anhedonia is manifest in individuals who carry genetic liability for schizophrenia and is associated with the Val(158)Met polymorphism of the COMT gene.
This study provides novel evidence for differential effects of the COMT gene on neural systems underlying visual perception in schizophrenia and bipolar disorder.
The subset of relatives of schizophrenia patients who were COMT val homozygotes exhibited lower scores on narcissism, rejectionality, and stimulus seeking than met homozygote relatives of schizophrenia patients and control participants.
These results support the hypothesis that the COMT Val(158)Met polymorphism influences executive functions in schizophrenia and the neuromotor performance in the deficit subtype only.
Catechol O-methyltransferase Val158Met polymorphism in schizophrenia: differential effects of Val and Met alleles on cognitive stability and flexibility.