| 1. |
- Andreou, Dimitrios, et al.
(författare)
-
d-amino acid oxidase activator gene (DAOA) variation affects cerebrospinal fluid homovanillic acid concentrations in healthy Caucasians
- 2012
-
Ingår i: European Archives of Psychiatry and Clinical Neuroscience. - : Springer Science and Business Media LLC. - 0940-1334 .- 1433-8491. ; 262:7, s. 549-556
-
Tidskriftsartikel (refereegranskat)abstract
- The d-amino acid oxidase activator (DAOA) protein regulates the function of d-amino oxidase (DAO), an enzyme that catalyzes the oxidative deamination of d-3,4-dihydroxyphenylalanine (D-DOPA) and d-serine. D-DOPA is converted to l-3,4-DOPA, a precursor of dopamine, whereas d-serine participates in glutamatergic transmission. We hypothesized that DAOA polymorphisms are associated with dopamine, serotonin and noradrenaline turnover in the human brain. Four single-nucleotide polymorphisms, previously reported to be associated with schizophrenia, were genotyped. Cerebrospinal fluid (CSF) samples were drawn by lumbar puncture, and the concentrations of the major dopamine metabolite homovanillic acid (HVA), the major serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA) and the major noradrenaline metabolite 3-methoxy-4-hydroxyphenylglycol (MHPG) were measured. Two of the investigated polymorphisms, rs3918342 and rs1421292, were significantly associated with CSF HVA concentrations. Rs3918342 was found to be nominally associated with CSF 5-HIAA concentrations. None of the polymorphisms were significantly associated with MHPG concentrations. Our results indicate that DAOA gene variation affects dopamine turnover in healthy individuals, suggesting that disturbed dopamine turnover is a possible mechanism behind the observed associations between genetic variation in DAOA and behavioral phenotypes in humans.
|
|
| 2. |
- Andreou, Dimitrios, et al.
(författare)
-
Dystrobrevin-binding protein 1 gene (DTNBP1) variants associated with cerebrospinal fluid homovanillic acid and 5-hydroxyindoleacetic acid concentrations in healthy volunteers
- 2011
-
Ingår i: European Neuropsychopharmacology. - : Elsevier BV. - 0924-977X .- 1873-7862. ; 21:9, s. 700-704
-
Tidskriftsartikel (refereegranskat)abstract
- The dystrobrevin binding protein-1 (DTNBP1) gene encodes dysbindin-1, a protein involved in neurodevelopmental and neurochemical processes related mainly to the monoamine dopamine. We investigated possible associations between eleven DTNBP1 polymorphisms and cerebrospinal fluid (CSF) concentrations of the major dopamine metabolite homovanillic acid (HVA), the major serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA), and the major noradrenaline metabolite 3-methoxy-4-hydroxyphenylglycol (MHPG) in healthy human subjects (n=132). Two polymorphisms, rs2619538 and rs760666, were nominally associated with CSF HVA and 5-HIAA concentrations, whereas a third polymorphism, rs909706, showed association only with HVA. After correction for multiple testing only the associations between rs2619538 and HVA and 5-HIAA concentrations remained significant. No significant association was found between any of the investigated DTNBP1 polymorphisms and CSF MHPG concentrations. The results suggest that genetic variation in DTNBP1 gene affects the regulation of dopamine and serotonin turnover in the central nervous system of healthy volunteers.
|
|
| 3. |
- Andreou, Dimitrios, et al.
(författare)
-
Tryptophan hydroxylase gene 1 (TPH1) variants associated with cerebrospinal fluid 5-hydroxyindole acetic acid and homovanillic acid concentrations in healthy volunteers
- 2010
-
Ingår i: Psychiatry Research. - : Elsevier BV. - 0165-1781 .- 1872-7123. ; 180:2-3, s. 63-67
-
Tidskriftsartikel (refereegranskat)abstract
- Tryptophan hydroxylase (TPH) is the rate-limiting enzyme in serotonin synthesis. We investigated possible relationships between five TPH1 gene polymorphisms and cerebrospinal fluid (CSF) concentrations of the major serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA), the major dopamine metabolite homovanillic acid (HVA), and the major norepinephrine metabolite 3-methoxy-4-hydroxyphenylglycol (MHPG) in healthy volunteers (n = 132). The G-allele of the TPH1 rs4537731 (A-6526G) polymorphism was associated with 5-HIM and HVA, but not MHPG concentrations. None of the other four TPH1 polymorphisms (rs211105, rs1800532, rs1799913 and rs7933505) were significantly associated with any of the monoamine metabolite concentrations. Two (rs4537731G/rs211105T/rs1800532C/rs1799913C/rs7933505G and rs4537731A/rs211105T/rs1800532C/rs1799913C/rs7933505G) of five common TPH1 five-allele haplotypes were associated with 5-HIAA and HVA concentrations in opposite directions. None of the common haplotypes was associated with MHPG concentrations in the CSF. The results suggest that TPH1 gene variation participates in the regulation of serotonin and dopamine turnover rates in the central nervous system of healthy human subjects.
|
|
| 4. |
|
|
| 5. |
- Jönsson, Erik G., et al.
(författare)
-
Two methylenetetrahydrofolate reductase gene (MTHFR) polymorphisms, schizophrenia and bipolar disorder : An association study
- 2008
-
Ingår i: American journal of medical genetics. Part B, Neuropsychiatric genetics. - : Wiley. - 1552-4841. ; 147B:6, s. 976-982
-
Tidskriftsartikel (refereegranskat)abstract
- Recent meta-analyses of the methylenetetrahydrofolate reductase gene (MTHFR) have suggested association between two of its functional single gene polymorphisms (SNPs, C677T and A1298C) and schizophrenia. Studies have also suggested association between MTHFR C677T and A1298C variation and bipolar disorder. In a replication attempt the MTHFR C677T and A1298C SNPs were analyzed in three Scandinavian schizophrenia case-control samples. In addition, Norwegian patients with bipolar disorder were investigated. There were no statistically significant allele or genotype case-control differences. The present Scandinavian results do not verify previous associations between the putative functional MTHFR gene polymorphisms and schizophrenia or bipolar disorder. However, when combined with previous studies in meta-analyses there is still evidence for association between the MTHFR C677T polymorphism. and schizophrenia. Additional studies are warranted to shed further light on these relationships. (c) 2007 Wiley-Liss, Inc.
|
|
| 6. |
- Saetre, Peter, et al.
(författare)
-
Association between a disrupted-in-schizophrenia 1 (DISC1) single nucleotide polymorphism and schizophrenia in a combined Scandinavian case-control sample
- 2008
-
Ingår i: Schizophrenia Research. - : Elsevier BV. - 0920-9964 .- 1573-2509. ; 106:2-3, s. 237-241
-
Tidskriftsartikel (refereegranskat)abstract
- Disrupted-in-schizophrenia-1 (DISC1), located on chromosome 1q42.1, is linked to rare familial schizophrenia in a large Scottish family. The chromosomal translocation that segregates with the disease results in a truncated protein that impairs neurite outgrowth and proper development of the cerebral cortex, suggesting that lost DISC1 function may underlie neurodevelopmental dysfunction in schizophrenia. DISC1 has been associated with schizophrenia in multiple populations, but there is little evidence of convergence across populations. In the present case-control study three Scandinavian samples of 837 individuals affected with schizophrenia and 1473 controls, were used in an attempt to replicate previously reported associations between single nucleotide polymorphisms (SNPs) in DISC1 and schizophrenia. No SNP with allele frequency above 10% was significantly associated with the disease after correction for multiple testing. However, the minor allele of rs3737597 (frequency 2%) in the 3'-untransiated region (UTR), previously identified as a risk allele in Finnish families, was significantly and consistently associated with the disorder across the three samples, (p-value corrected for multiple testing was 0.002). Our results suggest that a relatively uncommon DISC1 mutation, which increases the susceptibility for schizophrenia may be segregating in the Scandinavian population, and support the view that common DISC1 SNP alleles are unlikely to account for a substantial proportion of the genetic risk of the disease across populations of European descent.
|
|
| 7. |
- Saetre, Peter, et al.
(författare)
-
Methylenetetrahydrofolate Reductase (MTHFR) C677T and A1298C Polymorphisms and Age of Onset in Schizophrenia : A Combined Analysis of Independent Samples
- 2011
-
Ingår i: American Journal of Medical Genetics, Part B: Neuropsychiatric Genetics. - : Wiley. - 1552-4841. ; 156B156:2, s. 215-224
-
Tidskriftsartikel (refereegranskat)abstract
- Methylenetetrahydrofolate reductase (MTHFR) is involved in the one-carbon cycle, which is of importance for nucleotide synthesis and methylation of DNA, membranes, proteins and lipids. The MTHFR gene includes two common polymorphisms (rs1801133 or C677T; rs1801131 or A1298C) which both alter enzyme activity. The T-allele of the C677T polymorphism has recently been associated with earlier age at onset of schizophrenia. In the present study we examined the association between the MTHFR C677T and A1298C polymorphisms and age at onset of schizophrenia in twelve samples consisting of 3,213 unrelated schizophrenia patients, including the original Scandinavian sample. There was no consistent relationship between MTHFR C677T, A1298C or combined 677T/1298C carriers and age of onset in schizophrenia when the results of each study were combined using meta-analysis. The present results suggest that the investigated MTHFR polymorphisms do not influence age of onset in schizophrenia.
|
|
| 8. |
- Saetre, Peter, et al.
(författare)
-
The Tryptophan Hydroxylase 1 (TPH1) Gene, Schizophrenia Susceptibility, and Suicidal Behavior : A Multi-Centre Case-Control Study and Meta-Analysis
- 2010
-
Ingår i: American Journal of Medical Genetics, Part B: Neuropsychiatric Genetics. - : Wiley. - 1552-4841. ; 153B:2, s. 387-396
-
Tidskriftsartikel (refereegranskat)abstract
- Serotonin (5-hydroxytryptamin; 5-HT) alternations has since long been suspected in the pathophysiology of schizophrenia. Tryptophan hydroxylase (tryptophan 5-monooxygenase; TPH) is the rate-limiting enzyme in the biosynthesis of 5-HT, and sequence variation in intron 6 of the TPH1 gene has been associated with schizophrenia. The minor allele (A) of this polymorphism (A218C) is also more frequent in patients who have attempted suicide and individuals who died by suicide, than in healthy control individuals. In an attempt to replicate previous findings, five single nucleotide polymorphisms (SNPs) were genotyped in 837 Scandinavian schizophrenia patients and 1,473 controls. Three SNPs spanning intron 6 and 7, including the A218C and A779C polymorphisms, were associated with schizophrenia susceptibility (P = 0.019). However there were no differences in allele frequencies of these loci between affected individuals having attempted suicide at least once and patients with no history of suicide attempts (P=0.84). A systematic literature review and meta-analysis support the A218C polymorphism as a susceptibility locus for schizophrenia (odds ratio 1.17, 95% confidence interval 1.07-1.29). Association studies on suicide attempts are however conflicting (heterogeneity index I-2 = 0.54) and do not support the A218C/A779C polymorphisms being a susceptibility locus for suicidal behavior among individuals diagnosed with a psychiatric disorder (OR = 0.96 [0.80-1.16]). We conclude that the TPH1 A218/A779 locus increases the susceptibility of schizophrenia in Caucasian and Asian populations. In addition, the data at hand suggest that the locus contributes to the liability of psychiatric disorders characterized by elevated suicidal rates, rather than affecting suicidal behavior of individuals suffering from a psychiatric disorder.
|
|
| 9. |
- Vares, Maria, et al.
(författare)
-
Association Between Methylenetetrahydrofolate Reductase (MTHFR) C677T Polymorphism and Age of Onset in Schizophrenia
- 2010
-
Ingår i: American Journal of Medical Genetics, Part B: Neuropsychiatric Genetics. - : Wiley. - 1552-4841. ; 153B:2, s. 610-618
-
Tidskriftsartikel (refereegranskat)abstract
- Different lines of evidence indicate that methylenetetrahydrofolate reductase (MTHFR) functional gene polymorphisms, causative in aberrant folate-homocysteine metabolism, are associated with increased vulnerability to several heritable developmental disorders. Opposing views are expressed considering the possible association between MTHFR and susceptibility for schizophrenia. In order to evaluate if age of onset could explain some of this discrepancy we investigated the relationship between two functional MTHFR gene polymorphisms and age at onset in this disorder. Scandinavian patients (n = 820) diagnosed with schizophrenia, schizoaffective disorder, and schizophreniform disorder were investigated. Two functional MTHFR single nucleotide polymorphisms (SNPs; rs1801131 and rs1801133) were genotyped and the effect of MTHFR polymorphisms on the age of onset was examined with survival analysis. In an attempt to replicate the findings from the Scandinavian sample, the association between rs1801133 and age at onset was also analyzed in Chinese high-risk families, with two or more affected siblings (n = 243). Among the Scandinavian patients the functional MTHFR SNP rs1801133 (C677T) significantly affected age at onset of schizophrenia in a dose-dependent manner (P = 0.0015), with lower age of onset with increasing numbers of the mutant T-allele. There was no evidence of rs1801131 (A1298C) affecting age of onset in schizophrenia. Within the Chinese high-risk families carriers of the MTHFR 677T allele showed earlier age at onset than siblings being homozygous for the wild-type allele (P = 0.008). The MTHFR C677T polymorphism may play a role as a modifying factor for age of onset in schizophrenia.
|
|
