Multicentre Italian family-based association study on tyrosine hydroxylase, catechol-O-methyl transferase and Wolfram syndrome 1 polymorphisms in mood disorders

Interaction between COMT Val158 Met polymorphism and childhood trauma predicts risk for depression in men

Depression is a disabling illness with complex etiology. While the Catechol-O-Methyltransferase (COMT) gene, in particular the functional Val¹⁵⁸ Met polymorphism, has been related to depression, the mechanisms underlying this gene-disease association are not completely understood. Therefore, we explore the association of COMT Val¹⁵⁸ Met polymorphism with depression as well as its interaction with childhood trauma in 1,136 young adults from a population-based study carried out in the city of Pelotas-Brazil. The diagnosis was performed through the Mini International Neuropsychiatric Interview 5.0 (MINI 5.0), and trauma was assessed with the childhood trauma questionnaire (CTQ). Total DNA was extracted and genotyped by real-time PCR and the QTLbase dataset was queried to perform large-scale quantitative trait locus (QTL) analysis. Our research showed no direct association between the Val¹⁵⁸ Met polymorphism and the diagnosis of depression (women: χ2=0.10, d=1, p=0.751 and men: χ2=0.003, df=1 p=0.956). However, the Met-allele of the Val¹⁵⁸ Met polymorphism modified the effect of childhood trauma in men [OR=2.58 (95% CI:1.05-6.29); p=0.038] conferring risk for depression only on those who suffer from trauma. The conditional effect from moderation analysis showed that trauma impacts the risk of depression only in men carrying the Met-allele (Effect: 0.9490, Standard Error (SE): 0.2570; p=0.0002). QTLbase and dataset for Val¹⁵⁸ Met polymorphism were consistent for markers that influence chromatin accessibility transcription capacity including histone methylation and acetylation. The changes caused in gene regulation by childhood trauma exposure and polymorphism may serve as evidence of the mechanism whereby the interaction increases susceptibility to this disorder in men.

Molecular characterization of WFS1 in an Iranian family with Wolfram syndrome reveals a novel frameshift mutation associated with early symptoms

Wolfram syndrome (WS) is a rare autosomal recessive neurodegenerative disorder that represents a likely source of childhood diabetes especially among countries in the consanguinity belt. The main responsible gene is WFS1 for which over one hundred mutations have been reported from different ethnic groups. The aim of this study was to identify the molecular etiology of WS and to perform a possible genotype-phenotype correlation in Iranian kindred. An Iranian family with two patients was clinically studied and WS was suspected. Genetic linkage analysis via 5 STR markers was carried out. For identification of mutations, DNA sequencing of WFS1 including all the exons, exon-intron boundaries and the promoter was performed. Linkage analysis indicated linkage to the WFS1 region. After DNA sequencing of WFS1, one novel pathogenic mutation, which causes frameshift alteration c.2177_2178insTCTTC (or c.2173_2177dupTCTTC) in exon eight, was found. The genotype-phenotype correlation analysis suggests that the presence of the homozygous mutation may be associated with early onset of disease symptoms. This study stresses the necessity of considering the molecular analysis of WFS1 in childhood diabetes with some symptoms of WS.

European Group for the Study of Resistant Depression (GSRD)--where have we gone so far: review of clinical and genetic findings

The primary objective of this review is to give an overview of the main findings of the European multicenter project "Patterns of Treatment Resistance and Switching Strategies in Affective Disorder", performed by the Group for the Study of Resistant Depression (GSRD). The aim was to study methodological issues, operational criteria, clinical characteristics, and genetic variables associated with treatment resistant depression (TRD), that is failure to reach response after at least two consecutive adequate antidepressant trials. The primary findings of clinical variables associated with treatment resistance include comorbid anxiety disorders as well as non-response to the first antidepressant received lifetime. Although there is a plethora of hints in textbooks that switching the mechanism of action should be obtained in case of nonresponse to one medication, the results of the GSRD challenge this notion by demonstrating in retrospective and prospective evaluations that staying on the same antidepressant mechanism of action for a longer time is more beneficial than switching, however, when switching is an option there is no benefit to switch across class. The GSRD candidate gene studies found that metabolism status according to cytochrome P450 gene polymorphisms may not be helpful to predict response and remission rates to antidepressants. Significant associations with MDD and antidepressant treatment response were found for COMT SNPs. Investigating the impact of COMT on suicidal behaviour, we found a significant association with suicide risk in MDD patients not responding to antidepressant treatment, but not in responders. Further significant associations with treatment response phenotypes were found with BDNF, 5HTR2A and CREB1. Additional investigated candidate genes were DTNBP1, 5HT1A, PTGS2, GRIK4 and GNB3.

The impact of COMT gene polymorphisms on suicidality in treatment resistant major depressive disorder--a European multicenter study

Many association studies have reported associations between the catechol-O-methyltransferase (COMT) gene and psychiatric disorders including major depression (MDD). The COMT gene has further been associated with suicidal behaviour, as well as with treatment response, although with conflicting results. In the present study, we further elucidate the impact of COMT in treatment response in MDD patients with suicide risk and/or a personal history of suicide attempts. Two hundred fifty MDD patients were collected in the context of a European multicentre resistant depression study and treated with antidepressants at adequate doses for at least 4 weeks. Suicidality was assessed using Mini International Neuropsychiatric Interview (MINI) and the Hamilton Rating Scale for Depression (HAM-D). Treatment response was defined as HAM-D ≤ 17 and remission as HAM-D ≤ 7 after 4 weeks of treatment with antidepressants at adequate dose. Genotyping was performed for seven SNPs (rs4680, rs2075507, rs737865, rs6269, rs4633, rs4818 and rs165599) within the COMT gene. With regard to suicide risk and personal history of suicide attempts, neither single marker nor haplotypic association was found with any SNP after multiple testing correction. In non-responders, we found significant single marker and haplotypic association with suicide risk, but not in responders. The same holds true for both remitters and non-remitters, and when testing for association with a personal history of suicide attempts and treatment response phenotypes. In conclusion, we found significant association of COMT SNPs with suicide risk in MDD patients not responding to antidepressant treatment. Larger well-defined cohorts will be required to dissect this further.

The functional Val158Met polymorphism in catechol-O-methyltransferase (COMT) is associated with depression and motivation in men from a Swedish population-based study

BACKGROUND

Environmental risk factors together with genetic vulnerability create a complex background to develop depression.

METHODS

We investigated the associations between COMT Val(158)Met and depression in a Swedish population-based sample of 405 depressed individuals (major depression diagnosis, dysthymia or mixed anxiety depression defined according to DSM-IV) and 2,151 healthy controls. We also analyzed interaction between this genetic variation and some environmental risk factors for depression and the link between this polymorphism and the low motivational level and negative mood state found in depressed individuals.

RESULTS

Depressed individuals displayed a higher frequency of the Met/Met and Met/Val genotypes compared to controls (OR=1.49, CI(95%)=1.11-2.00, P=0.009). The association was found among men only (OR=2.26, CI(95%)=1.26-4.05, p=0.008). Regression analysis including some potential risk factors for depression, did further indicate that Met/Met and Met/Val were associated with depression in men (P=0.005). There was also an interaction between genotype and family childhood problems (RERI=0.876, CI(95%)=0.090-1.662 and AP=0.426, CI(95%)=0.030-0.821). Further, depressed men homozygous for the Val-allele, had a higher motivational level than depressed men with a Met-variant (P=0.02).

LIMITATIONS

The sample size of depressed individuals per group when stratifying cases according to gender and genotypes is considered a limitation.

CONCLUSIONS

The Met-variants of COMT Val(158)Met are risk variants for depression and low motivational level in depressed Swedish men, but not women. Individuals with this risk variant in combination with a problematic childhood, have an even higher risk to develop depression.

Do COMT, BDNF and NRG1 polymorphisms influence P50 sensory gating in psychosis?

BACKGROUND

Auditory P50 sensory gating deficits correlate with genetic risk for schizophrenia and constitute a plausible endophenotype for the disease. The well-supported role of catechol-O-methyltransferase (COMT), brain-derived neurotrophic factor (BDNF) and neuregulin 1 (NRG1) genes in neurodevelopment and cognition make a strong theoretical case for their influence on the P50 endophenotype.

METHOD

The possible role of NRG1, COMT Val158Met and BDNF Val66Met gene polymorphisms on the P50 endophenotype was examined in a large sample consisting of psychotic patients, their unaffected relatives and unrelated healthy controls using linear regression analyses.

RESULTS

Although P50 deficits were present in patients and their unaffected relatives, there was no evidence for an association between NRG1, COMT Val158Met or BDNF Val66Met genotypes and the P50 endophenotype.

CONCLUSIONS

The evidence from our large study suggests that any such association between P50 indices and NRG1, COMT Val158Met or BDNF Val66Met genotypes, if present, must be very subtle.

Catechol-O-methyltransferase Val158Met polymorphism affects therapeutic response to mood stabilizer in symptomatic manic patients

Catechol-O-methyltransferase (COMT) is a candidate gene for the pathogenesis of some psychiatric disorders. The aim of this study is to examine the role of the COMT gene Val158Met polymorphism on the clinical aspects of bipolar disorder including symptomatology and therapeutic response. This study comprised 144 unrelated manic patients who met strict DSM-IV criteria for bipolar I disorder and 157 healthy unrelated controls. All subjects were of Korean ethnicity. To evaluate the clinical symptoms, we used the Young Mania Rating Scale at baseline and 6 weeks after treatment. No statistically significant difference in genotype distribution was found between manic patients and normal controls. There was also no significant difference in symptomatology among the genotypes in manic patients. In therapeutic response, however, patients with the Met/Met genotype were significantly more frequent in the non-responder than in the responder group. Our results suggest that the COMT gene polymorphism in the therapeutic response to mood stabilizers in manic patients. Further studies with a larger number of subjects and well-controlled design will be required to better understand the role of the COMT gene polymorphism on the therapeutic response to mood stabilizer in manic patients.

COMT val158met influence on electroconvulsive therapy response in major depression

There is strong evidence for a genetic contribution to the pathogenesis of depression, with the functional catechol-O-methyltransferase (COMT) val158met polymorphism having been suggested as a potential susceptibility factor. In the present study, the effect of COMT val158met on response to electroconvulsive therapy (ECT) was analyzed in a sample of 104 Caucasian patients (f = 71, m = 33) with pharmacologically treatment-resistant Major Depression. The higher active COMT 158val allele was found to be associated with (1) higher pre-ECT severity of depression and (2) better treatment response to ECT particularly regarding the core symptoms of depression as well as sleep-related symptoms. These findings were restricted to the female subgroup of patients. In summary, the present study supports a potentially gender-specific significant impact of COMT gene variation on electroconvulsive therapy response, with COMT 158val risk allele carriers suffering from more severe, pharmacologically less efficiently treatable depression and thus possibly deriving greater benefit from ECT in the first place.

Wolframin gene H611R polymorphism: no direct association with suicidal behavior but possible link to mood disorders

Wolframin gene polymorphisms, including the H611R polymorphism, are reportedly associated with mood disorders and psychiatric hospitalization, but there is disagreement about the association of this specific variant with suicidality and impulsive traits. This study tested the association of the H611R polymorphism with mood disorders, suicidal behavior, and aggressive-impulsive traits. Two hundred and one subjects with mood disorders and 113 healthy volunteers were genotyped for the H611R polymorphism and underwent structured interviews for diagnosis and clinical ratings. All were Caucasians. The H611R polymorphism was associated with mood disorders but not suicidal behavior, aggressive/impulsive traits or suicidality in first-degree relatives. The HR heterozygote genotype was more frequent in mood disorder (chi(2)=7.505; df=2; p=.023). If this finding will be replicated, the H611R polymorphism may be a possible marker for mood disorders in a psychiatric population, and not just in relatives of Wolfram syndrome probands.

Association study of candidate variants of COMT with neuroticism, anxiety and depression

The Val158Met polymorphism of the gene encoding catechol-O-methyltransferase (COMT) is one of the most widely tested variants for association with psychiatric disorders, but replication has been inconsistent including both sex limitation and heterogeneity of the associated allele. In this study we investigate the association between three SNPs from COMT and anxiety and depression disorders and neuroticism all measured within the same study sample. Participants were selected as sibling pairs (or multiples) that were either concordant or discordant for extreme neuroticism scores from a total sample of 18,742 Australian twin individuals and their siblings. All participants completed the Composite International Diagnostic Interview (CIDI) from which diagnoses of DSM-IV depression and anxiety disorders were determined. Of the participants, 674 had a diagnosis of anxiety and/or depression from 492 families. Study participants (n = 2,045 from 987 families) plus, where possible, their parents were genotyped for rs737865, rs4680 (Val158Met), and rs165599. Using family based tests we looked for association between these variants and neuroticism, depression, anxiety, panic disorder and agarophobia (PDAG) and obsessive compulsive disorder. We found no convincing evidence for association either in allelic or genotypic tests for the total sample or when the sample was stratified by sex. Haplotype T-G-G showed weak association (P = 0.042) with PDAG before correction for multiple testing; association between this haplotype and schizophrenia has been previously reported in an Australian sample.

Experiential and genetic contributions to depressive- and anxiety-like disorders: clinical and experimental studies

Stressful events have been implicated in the precipitation of depression and anxiety. These disorders may evolve owing to one or more of an array of neuronal changes that occur in several brain regions. It seems likely that these stressor-provoked neurochemical alterations are moderated by genetic determinants, as well as by a constellation of experiential and environmental factors. Indeed, animal studies have shown that vulnerability to depressive-like behaviors involve mechanisms similar to those associated with human depression (e.g., altered serotonin, corticotropin releasing hormone and their receptors, growth factors), and that the effects of stressors are influenced by previous stressor experiences, particularly those encountered early in life. These stressor effects might reflect sensitization of neuronal functioning, phenotypic changes of processes that lead to neurochemical release or receptor sensitivity, or epigenetic processes that modify expression of specific genes associated with stressor reactivity. It is suggested that depression is a life-long disorder, which even after effective treatment, has a high rate of re-occurrence owing to sensitized processes or epigenetic factors that promote persistent alterations of gene expression.