No association of catechol-O-methyltransferase polymorphisms with schizophrenia in the Han Chinese population

Association between COMT gene rs165599 SNP and schizophrenia: A meta-analysis of case-control studies

BACKGROUND

There are many studies with different results that examine the association between Catechol-O-MethylTransferase (COMT) gene single-nucleotide polymorphisms (SNPs) and schizophrenia. In this study, the aim was to conduct a meta-analysis to achieve a pooled effect size of the association between COMT gene rs165599 SNP and schizophrenia.

METHODS

Odds ratio (OR) was used as an effect size to determine the association between schizophrenia and the SNP. The pooled ORs were achieved under four different genetic models. When the heterogeneity among studies was high the DerSimonian-Laird random-effects model, otherwise the Mantel-Haenszel fixed-effects model was used. Publication bias was evaluated by Egger's test.

RESULTS

Under different genetic models no statistically significant association was found between rs165599 SNP and schizophrenia by meta-analyses consist of 20 independent studies. There was high heterogeneity among studies, for the possible reason the population differences, although the subgroup analyzes reduced the heterogeneity, no association was obtained. However, the sex-specific estimation of the females showed that to be a G allele carrier is a risk factor for schizophrenia (OR = 1.366 [95% confidence interval = 1.094-1.706]) compared to AA homozygous.

CONCLUSION

The COMT gene rs165599 SNP does not appear to be a single-risk factor for schizophrenia.

BDNF rs 6265 polymorphism and COMT rs 4680 polymorphism in deficit schizophrenia in Polish sample

BACKGROUND

Deficit schizophrenia (DS) is distinguished from the group of schizophrenic psychoses based on the presence of primary negative symptoms. It differs from nondeficit (NDS) forms of schizophrenia in dimensions such as risk factors, family history, course of illness and neurobiological differences. The aim of the study was assessment of a potential association of the investigated polymorphisms of the brain-derived neurotrophic factor (BDNF) and catechol-O-methyltransferase (COMT) genes with the deficit syndrome in schizophrenia.

METHODS

A cohort of 200 patients with schizophrenia (81 DS and 119 NDS subjects) and a group of 100 control subjects matched for ethnicity, sex and age were recruited. Somatic and psychometric assessment were conducted as well as structured interview about the influence of adverse biological, family and social factors. Genetic analysis of the BDNF (Val66Met) rs6265 and the COMT (Val158Met) rs4680 polymorphisms was performed.

RESULTS

We found significant differences between DS and NDS in rs4680 COMT genotype distribution: more homozygous Val/Val were found (31 vs. 17%) in the NDS compared to the DS subgroup. No associations were found between the investigated polymorphisms of the BDNF gene and the presence of schizophrenia either in DS and NDS subgroups.

CONCLUSION

The analysis of the COMT rs4680 polymorphism in the present DS and NDS study shows that some genetic factors may be relevant in analyzing the reasons for the differentiation of schizophrenic subtypes.

Peptide sharing between influenza A H1N1 hemagglutinin and human axon guidance proteins

Epidemiologic data suggest that maternal microbial infections may cause fetal neurodevelopmental disorders, potentially increasing susceptibility to heavy psychopathologies such as schizophrenia, schizophreniform disorder, autism, pervasive developmental disorders, bipolar disorders, psychosis, epilepsy, language and speech disorders, and cognitive impairment in adult offspring. However, the molecular pathomechanisms underlying such a relationship are not clear. Here we analyze the potential role of the maternal immune response to viral infection in determining fetal brain injuries that increase the risk of neurological disorders in the adult. We use influenza infection as a disease model and human axon guidance pathway, a key process in the formation of neural network during midgestation, as a potential fetal target of immune insults. Specifically, we examined influenza A H1N1 hemagglutinin (HA), an antigenic viral protein, for amino acid sequence similarity to a random library of 188 axon guidance proteins. We obtain the results that (1) contrary to any theoretical expectations, 45 viral pentapeptide matches are distributed throughout a subset of 36 guidance molecules; (2) in 24 guidance proteins, the peptide sharing with HA antigen involves already experimentally validated influenza HA epitopes; and (3) most of the axon guidance vs HA peptide overlap is conserved among influenza A viral strains and subsets. Taken together, our data indicate that immune cross-reactivity between influenza HA and axon guidance molecules is possible and may well represent a pathologic mechanism capable of determining neurodevelopmental disruption in the fetus.