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Zhou N, Yu Q, Li X, Yu Y, Kou C, Li W, Xu H, Luo X, Zuo L, Kosten TR, Zhang XY. Association of the dopamine β-hydroxylase 19 bp insertion/deletion polymorphism with positive symptoms but not tardive dyskinesia in schizophrenia. Hum Psychopharmacol 2013; 28:230-7. [PMID: 23559427 DOI: 10.1002/hup.2311] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Accepted: 02/28/2013] [Indexed: 01/29/2023]
Abstract
OBJECTIVE Overactivity of dopaminergic neurotransmission is a putative mechanism of tardive dyskinesia (TD). Dopamine beta-hydroxylase (DBH) is a key enzyme in the conversion of dopamine to norepinephrine, and plasma DBH activity is altered in TD patients. This study examined whether the functional DBH 5'-Ins/Del polymorphism was associated with TD severity in Chinese patients with schizophrenia. METHODS We compared the rate of this polymorphism in patients with (n = 312) and without TD (n = 435), and healthy controls (n = 625). The severity of TD was assessed using the Abnormal Involuntary Movement Scale (AIMS) and psychopathology using the Positive and Negative Syndrome Scale (PANSS). RESULTS There were no significant differences in the distribution of the allele and genotype frequencies between the patients and controls, or between the patients with and without TD. Also, there was no significant difference in the AIMS total score between the three genotype groups. However, the PANSS positive symptom subscore was significantly higher in patients with Del/Del genotype (13.2 ± 5.2) than those with Ins/Del (11.2 ± 4.9) and Ins/Ins (11.1 ± 3.1) genotypes (both p < 0.05). CONCLUSION These results suggest that although the DBH 5'-Ins/Del polymorphism was not associated with susceptibility to TD in patients with schizophrenia, it might be related to positive symptoms of schizophrenia.
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Affiliation(s)
- Na Zhou
- School of Basic Medicine, Jilin University, Changchun, China
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2
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Abstract
Genetic epidemiology has provided consistent evidence that schizophrenia has a genetic component It is now clear that this genetic component is complex and polygenic, with several genes interacting in epistasis. Although molecular studies have failed to identify any DNA variant that clearly contributes to vulnerability to schizophrenia, several regions have been implicated by linkage studies. To overcome the difficulties in the search for schizophrenia genes, it is necessary (i) to use methods of analysis that are appropriate for complex multifactorial disorders; (ii) to gather large enough clinical samples; and (iii) in the absence of genetic validity of the diagnostic classification currently used, to apply new strategies in order to better define the affected phenotypes. For this purpose, we describe here two strategies: (i) the candidate symptom approach, which concerns affected subjects and uses proband characteristics as the affected phenotype, such as age at onset, severity, and negative/positive symptoms; and (ii) the endophenotypic approach, which concerns unaffected relatives and has already provided positive findings with phenotypes, such as P50 inhibitory gating or eye-movement dysfunctions.
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Affiliation(s)
- M Leboyer
- Service de psychiatrie adulte, CHU Albert Chenevier et Henri Mondor, Université Paris XII, Créteil, France
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Barlas IÖ, Semiz U, Erdal ME, Algül A, Ay OI, Ateş MA, Camdeviren H, Basoglu C, Herken H. Association between dopamine beta hydroxylase gene polymorphism and age at onset in male schizophrenia. Acta Neuropsychiatr 2012; 24:176-82. [PMID: 26953012 DOI: 10.1111/j.1601-5215.2011.00617.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVES The heterogeneity of schizophrenia mainly results from variations in clinical expressions of the disease, such as age at onset, gender differences in onset of illness, symptoms and response to antipsychotic treatment. Enhanced sensitisation of dopamine pathways in males, having consistently an earlier onset, might be implicated as disease modifiers for schizophrenia in males. METHODS In this study, we performed a case (n = 87)-control (n = 100) association study between the DBH5'-ins/del and DBH-444g/a polymorphisms of the DBH gene and also compared the level of psychotic symptoms between patients with different DBH genotypes/haplotypes with respect to antipsychotic therapeutic response and gender difference. RESULTS No significant differences between allele and genotype and haplotype frequencies at either groups (p < 0.05). When the age is considered in patient group, a significant difference was observed between patients with ID genotype and with II genotype (p = 0.018). Patients with ID genotype have been diagnosed as schizophrenics in early ages when compared to II genotype carriers. We also found a significant difference between II and ID genotype (p = 0.007) when the gender had taken into account, showing that the ID genotype carriers had an early onset to schizophrenia. CONCLUSIONS This association was more significant in male schizophrenia patients than females. Thus, this finding may constitute a novel biological support for the prior finding that onset of schizophrenia varies with gender. The results also showed that critical genetic vulnerability may be associated with the presence or absence of the ID genotype of DBH5'-ins/del.
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Affiliation(s)
- I Ö Barlas
- Department of Medical Biology and Genetics, Medical Faculty of Mersin University, Mersin, Turkey
| | - Umit Semiz
- Department of Psychiatry, GATA Haydarpasa Training Hospital, Istanbul, Turkey
| | - M E Erdal
- Department of Medical Biology and Genetics, Medical Faculty of Mersin University, Mersin, Turkey
| | - Ayhan Algül
- Department of Psychiatry, GATA Haydarpasa Training Hospital, Istanbul, Turkey
| | - Ozlem I Ay
- Department of Medical Biology and Genetics, Medical Faculty of Mersin University, Mersin, Turkey
| | - M A Ateş
- Department of Psychiatry, GATA Haydarpasa Training Hospital, Istanbul, Turkey
| | - Handan Camdeviren
- Department of Biostatistics, Medical Faculty of Duzce University, Düzce, Turkey
| | - Cengiz Basoglu
- Department of Psychiatry, GATA Haydarpasa Training Hospital, Istanbul, Turkey
| | - Hasan Herken
- Department of Psychiatry, Faculty of Medicine, Pamukkale University, Denizli, Turkey
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4
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The dopamine b-hydroxylase 19 bp insertion/deletion polymorphism was associated with first-episode but not medicated chronic schizophrenia. J Psychiatr Res 2012; 46:733-7. [PMID: 22445279 DOI: 10.1016/j.jpsychires.2012.02.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2011] [Revised: 02/14/2012] [Accepted: 02/23/2012] [Indexed: 11/20/2022]
Abstract
BACKGROUND Numerous studies report dysfunctional dopaminergic and noradrenergic neurotransmission in the pathogenesis of schizophrenia. Dopamine beta-hydroxylase (DBH) is an intracellular enzyme catalyzing the conversion of dopamine to noradrenaline. Functional polymorphisms have been reported in the promoter region of DBH gene, including a 19 bp insertion/deletion polymorphism. The purpose of this study was to investigate whether there was an association between the functional polymorphism (DBH5'-Ins/Del) and schizophrenia in a Han Chinese population. METHODS This polymorphism was genotyped in 221 first-episode schizophrenics, 360 chronic schizophrenics and 318 healthy controls using a case-control design. We assessed their psychopathology using the Positive and Negative Syndrome Scale (PANSS). RESULTS We showed that the DBH5'-Ins/Del deletion (Del) allelic and genotypic frequencies were significantly lower in controls than first-episode of schizophrenics (FES) (both p < 0.001), but controls were not different from chronic schizophrenics. Furthermore, the PANSS positive symptom and total scores were significantly higher in FES with the Del/Del genotype than those with Ins/Del and Ins/Ins genotypes (all p < 0.05). CONCLUSIONS The DBH5'-Ins/Del polymorphism may play a role in susceptibility to the positive symptoms of FES and to these FES not progressing on to chronic schizophrenia.
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Pal P, Mihanović M, Molnar S, Xi H, Sun G, Guha S, Jeran N, Tomljenović A, Malnar A, Missoni S, Deka R, Rudan P. Association of tagging single nucleotide polymorphisms on 8 candidate genes in dopaminergic pathway with schizophrenia in Croatian population. Croat Med J 2009; 50:361-9. [PMID: 19673036 PMCID: PMC2728391 DOI: 10.3325/cmj.2009.50.361] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2009] [Accepted: 05/25/2009] [Indexed: 11/05/2022] Open
Abstract
AIM To perform a comprehensive evaluation of association of common genetic variants in candidate genes in the dopaminergic pathway with schizophrenia in a sample from Croatian population. METHODS A case-control association study was performed on 104 unrelated patients with schizophrenia recruited from a psychiatric hospital in Zagreb and 131 phenotypically normal Croatian subjects. Forty-nine tagging single nucleotide polymorphisms (tagSNPs) in 8 candidate genes in the dopaminergic pathway were identified from the HapMap database and tested for association. Genotyping was performed using the SNPlex platform. Statistical analysis was conducted to assess allelic and genotypic associations between cases and controls using a goodness of fit chi(2) test and trend test, respectively; adjustment for multiple testing was done by permutation based analysis. RESULTS Significant allele frequency differences between schizophrenia cases and controls were observed at 4 tagSNPs located in the genes DRD5, HTR1B1, DBH, and TH1 (P<0.005). A trend test also confirmed the genotypic association (P<0.001) of these 4 tagSNPs. Additionally, moderate association (P<0.05) was observed with 8 tagSNPs on SLC6A3, DBH, DRD4, SLC6A4, and COMT. CONCLUSIONS Common genetic variants in genes involved in the dopaminergic pathway are associated with schizophrenia in the populations of Caucasian descent.
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Affiliation(s)
- Prodipto Pal
- Department of Environmental Health, Center for Genome Information, University of Cincinnati, Cincinnati, OH, USA
| | | | - Sven Molnar
- St. Ivan Psychiatric Hospital, Zagreb, Croatia
| | - Huifeng Xi
- Department of Environmental Health, Center for Genome Information, University of Cincinnati, Cincinnati, OH, USA
| | - Guangyun Sun
- Department of Environmental Health, Center for Genome Information, University of Cincinnati, Cincinnati, OH, USA
| | - Saurav Guha
- Department of Environmental Health, Center for Genome Information, University of Cincinnati, Cincinnati, OH, USA
| | - Nina Jeran
- Institute for Anthropological Research, Zagreb, Croatia
| | | | - Ana Malnar
- Institute for Anthropological Research, Zagreb, Croatia
| | - Saša Missoni
- Institute for Anthropological Research, Zagreb, Croatia
| | - Ranjan Deka
- Department of Environmental Health, Center for Genome Information, University of Cincinnati, Cincinnati, OH, USA
| | - Pavao Rudan
- Institute for Anthropological Research, Zagreb, Croatia
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6
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Brown JS. Identification of candidate genes for schizophrenia based on natural resistance to infectious diseases. Acta Neuropsychiatr 2003; 15:108-14. [PMID: 26983352 DOI: 10.1034/j.1601-5215.2003.00018.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND Identification of candidate genes for schizophrenia may be more successful than genome screens as the latter have not found consistent linkages. OBJECTIVE To assist in the gene search, a model of schizophrenia based on resistance to infectious diseases, rather than susceptibility, is proposed. The theory blends the geography of schizophrenia with the assumption that genes that cause schizophrenia likely evolved and persist from selection pressure. The theory includes the notion that schizophrenia enhances biological survival at the cost of psychological and social functioning. METHOD To demonstrate the utility of using this model, the Medline literature was searched for resistance genes, mostly identified in mice. RESULTS Based on homologous locations in the human genome, these resistance genes are shown to be located in human chromosome regions linked significantly, in at least one genome screen, with schizophrenia or some physiologically related function or condition associated with schizophrenia. CONCLUSIONS The infectious disease resistance theory of schizophrenia is offered as a viable model for understanding the origins of schizophrenia. The theory also allows for the inclusion of persistent infections, seasonal variability and translational pathophysiology to contribute to the etiology of schizophrenia.
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Affiliation(s)
- James S Brown
- 1McGuire Veterans Affairs Medical Center, Richmond, Virginia, USA
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7
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Abstract
Genetic epidemiology has provided consistent evidence over many years that schizophrenia has a genetic component, and that this genetic component is complex, polygenic, and involves epistatic interaction between loci. Molecular genetics studies have, however, so far failed to identify any DNA variant that can be demonstrated to contribute to either liability to schizophrenia or to any identifiable part of the underlying pathology. Replication studies of positive findings have been difficult to interpret for a variety of reasons. First, few have reproduced the initial findings, which may be due either to random variation between two samples in the genetic inputs involved, or to a lack of power to replicate an effect at a given alpha level. Where positive data have been found in replication studies, the positioning of the locus has been unreliable, leading no closer to positional cloning of genes involved. However, an assessment of all the linkage studies performed over the past ten years does suggest a number of regions where positive results are found numerous times. These include regions on chromosomes 1, 2, 4, 5, 6, 7, 8, 9, 10, 13, 15, 18, 22 and the X. All of these data are critically reviewed and their locations compared. Reasons for the difficulty in obtaining consistent results and possible strategies for overcoming them are discussed. Am. J. Med. Genet. (Semin. Med. Genet.) 97:23-44, 2000.
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Affiliation(s)
- B P Riley
- MRC Research Fellow, Department of Psychological Medicien and the Social Genetic and Developmental Psychiatry Research Centre, Institute of Psychiatry, Kings college, London.
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8
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Yamamoto K, Cubells JF, Gelernter J, Benkelfat C, Lalonde P, Bloom D, Lal S, Labelle A, Turecki G, Rouleau GA, Joober R. Dopamine beta-hydroxylase (DBH) gene and schizophrenia phenotypic variability: a genetic association study. Am J Med Genet B Neuropsychiatr Genet 2003; 117B:33-8. [PMID: 12555232 DOI: 10.1002/ajmg.b.10011] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Recently, two polymorphisms (DBH5'-Ins/del and DBH 444 g/a) of the Dopamine Beta Hydroxylase (DBH) gene were isolated, and one haplotype (Del-a) was found to be associated with low DBH activity and cocaine-induced paranoia. The purpose of this study is to test for association between these two polymorphisms and schizophrenia or its phenotypic variability with respect to neuroleptic therapeutic response and symptom profile. Allelic and haplotype distributions of these two polymorphisms were compared between two groups of schizophrenic patients (excellent neuroleptic-responders; R, n = 42 and non-responders; NR, n = 64), and one group of healthy volunteers (n = 120). The "Del" and "a" alleles were in positive linkage disequilibrium. No allelic or genotype differences in the distribution of these two polymorphisms were observed between patients and controls. However, The Del-a haplotype was significantly more common in NR patients, and the mean total BPRS score was significantly higher in the group of patients with the Del-a compared to those without the Del-a haplotype. These results suggest that the DBH gene is not a causative factor in schizophrenia but that it may be a modulator of psychotic symptoms, severity of the disorder and therapeutic response to neuroleptic drugs.
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Affiliation(s)
- Kenji Yamamoto
- Douglas Hospital Research Centre; 6875 Boulevard LaSalle, Verdun H4H 1R3, Canada
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9
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Bailer U, Leisch F, Meszaros K, Lenzinger E, Willinger U, Strobl R, Heiden A, Gebhardt C, Döge E, Fuchs K, Sieghart W, Kasper S, Hornik K, Aschauer HN. Genome scan for susceptibility loci for schizophrenia and bipolar disorder. Biol Psychiatry 2002; 52:40-52. [PMID: 12079729 DOI: 10.1016/s0006-3223(02)01320-3] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Despite the widely accepted view that schizophrenia and bipolar disorder represent independent illnesses and modes of inheritance, some data in the literature suggest that the diseases may share some genetic susceptibility. The objective of our analyses was to search for vulnerability loci for the two disorders. METHODS A genomewide map of 388 microsatellite DNA markers was genotyped in five schizophrenia and three bipolar disorder Austrian families. Linkage analyses was used to compute the usual parametric logarithm of the likelihood of linkage (LOD) scores and nonparametric linkage analysis (NPL scores Z(all)) was used to assess the pattern of allele sharing at each marker locus relative to the presence of the disease (GENEHUNTER). Affected status was defined as severe affective disorder or schizophrenia. RESULTS Across the genome, p values associated with NPL scores resulted in evidence (i.e., p <.0007) for linkage at marker D3S1265 on chromosome 3q (NPL score Z (all) = 3.74, p =.0003). Two other markers (on 3q and 6q) showed p values of <.01. CONCLUSIONS We detected a potential susceptibility locus for bipolar disorder and schizophrenia on chromosome 3q, which has not been reported previously. The possibility of a false positive result has to be taken into account. Our data suggest shared loci for schizophrenia and bipolar affective disorders and are consistent with the continuum model of psychosis.
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Affiliation(s)
- Ursula Bailer
- Department of General Psychiatry, University Hospital for Psychiatry, Vienna, Austria
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10
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Prasad S, Semwal P, Deshpande S, Bhatia T, Nimgaonkar VL, Thelma BK. Molecular genetics of schizophrenia: past, present and future. J Biosci 2002; 27:35-52. [PMID: 11927776 DOI: 10.1007/bf02703682] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Schizophrenia is a severe neuropsychiatric disorder with a polygenic mode of inheritance which is also governed by non-genetic factors. Candidate genes identified on the basis of biochemical and pharmacological evidence are being tested for linkage and association studies. Neurotransmitters, especially dopamine and serotonin have been widely implicated in its etiology. Genome scan of all human chromosomes with closely spaced polymorphic markers is being used for linkage studies. The completion and availability of the first draft of Human Genome Sequence has provided a treasure-trove that can be utilized to gain insight into the so far inaccessible regions of the human genome. Significant technological advances for identification of single nucleo-tide polymorphisms (SNPs) and use of microarrays have further strengthened research methodologies for genetic analysis of complex traits. In this review, we summarize the evolution of schizophrenia genetics from the past to the present, current trends and future direction of research.
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Affiliation(s)
- Suman Prasad
- Department of Genetics, University of Delhi South Campus, Benito Juarez Road, New Delhi 110 021, India
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11
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Meszaros K, Lenzinger E, Hornik K, Füreder T, Stompe T, Willinger U, Heiden A, Fathi N, Gerhard E, Fuchs K, Sieghart W, Kasper S, Aschauer HN. Association study of schizophrenia spectrum disorders and dopamine D3 receptor gene: is schizoaffective disorder special? Psychiatry Res 2000; 96:179-83. [PMID: 11063791 DOI: 10.1016/s0165-1781(00)00209-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Alterations in dopamine neurotransmission have been hypothesized to play a role in the etiology of schizophrenia. We considered the dopamine D3 receptor gene on chromosome 3 as a candidate gene for an association analysis. We compared PCR-based genotype markers for healthy controls (n=120) and patients (n=95) with schizophrenia and schizophrenia spectrum disorders as diagnosed by consensus according to DSM-III-R. Our results possibly indicate an association of schizoaffective disorder with DRD3 homozygosity (P=0.056).
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Affiliation(s)
- K Meszaros
- University Hospital for Psychiatry, Department of General Psychiatry, Währinger Gürtel 18-20, A-1090, Vienna, Austria
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12
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Kunugi H. Candidate Gene Approaches to Schizophrenia. INTERNATIONAL JOURNAL OF MENTAL HEALTH 2000. [DOI: 10.1080/00207411.2000.11449496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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13
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Arrufat FJ, Diaz R, Queralt R, Navarro V, Marcos T, Massana G, Massana J, Ballesta F, Oliva R. Analysis of the polymorphic (GT)(n) repeat at the dopamine beta-hydroxylase gene in Spanish patients affected by schizophrenia. AMERICAN JOURNAL OF MEDICAL GENETICS 2000; 96:88-92. [PMID: 10686559 DOI: 10.1002/(sici)1096-8628(20000207)96:1<88::aid-ajmg18>3.0.co;2-v] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The presence of a polymorphic (GT)(n) repeat, a microsatellite repeat, at the human dopamine beta-hydroxylase (DBH) gene had been previously investigated in healthy people and in schizophrenic patients. The different DBH genotypes had been found to be associated to different DBH biochemical function, but no differences were found in the allelic and genotype frequencies between schizophrenic and control groups. To further clarify the potential involvement of the variation at the DBH gene in schizophrenia we have studied the DBH (GT)(n) repeat in a sample of 47 Spanish schizophrenic patients, in their healthy relatives (n = 72), and in a control population (n = 74). We have been able to identify five different variants of the DBH gene (A1, A2, A3, A4, A5) in the different groups. Subsequent statistical analysis revealed that the genotypes as well as the allele frequencies did not differ significantly among schizophrenic patients and the control population. Interestingly, the allelic variant A2 and the genotype A4/A2 were significantly more frequent in schizophrenic patients as compared with their healthy relatives. However, the association of the A2 allele with schizophrenia was not supported by the haplotype relative risk analysis of transmitted versus nontransmitted alleles. Therefore, although it will be important to extend the present analysis in a larger sample of schizophrenic patients and controls, our results suggest that the (GT)(n) does not seem to play a major role in the genetics of schizophrenia at least in this group of Spanish schizophrenic patients. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:88-92, 2000.
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Affiliation(s)
- F J Arrufat
- Centro de Salud Mental, Hospital de Sabadell, Corporación Sanitaria Parc Taulí, Sabadell, Barcelona, Spain
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14
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Williams HJ, Bray N, Murphy KC, Cardno AG, Jones LA, Owen MJ. No evidence for allelic association between schizophrenia and a functional variant of the human dopamine beta-hydroxylase gene (DBH). AMERICAN JOURNAL OF MEDICAL GENETICS 1999; 88:557-9. [PMID: 10490716 DOI: 10.1002/(sici)1096-8628(19991015)88:5<557::aid-ajmg22>3.0.co;2-f] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Dopamine beta-hydroxylase (DBH), the enzyme that converts dopamine to norepinepherine, has been proposed as being involved in the aetiology of schizophrenia. Previous work identified a functional polymorphism at nucleotide 910 of the DBH gene that results in a codon change in the mature protein Ala304Ser, with the mutant allele being associated with a lower enzymatic activity. In this study we performed an RFLP analysis in an association study consisting of 178 unrelated schizophrenic patients and 178 unrelated control subjects, matched for age, sex, and ethnicity. The frequency of the Ser304 DBH allele was 0.10 in the patient group and 0.08 in the control group, with no significant allelic or genotypic association observed. Therefore, we were unable to obtain evidence that this polymorphism contributes directly to susceptibility to schizophrenia.
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Affiliation(s)
- H J Williams
- Neuropsychiatric Genetics Department, University of Wales College of Medicine, Cardiff, United Kingdom.
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15
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Abstract
Glutaminyl cyclase (QC) is responsible for the presence of pyroglutamyl residues in many neuroendocrine peptides. An examination of the bovine tissue distribution of QC immunoreactivity, enzyme activity, and mRNA confirmed that QC was abundant in brain and pituitary by all three measures. However, enzymatic activity was considerably more widespread than either immunoreactivity or mRNA, suggesting multiple enzyme forms. Partially purified QC from bovine spleen differed significantly from the known bovine pituitary QC in physical and catalytic properties. We propose that this form of glutaminyl cyclase plays a role in the posttranslational processing of constitutively secreted pGlu-containing proteins.
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Affiliation(s)
- P A Sykes
- Department of Chemistry and Biochemistry, The University of Southern Mississippi, Hattiesburg 39406-5043, USA
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16
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Kaufmann CA, Suarez B, Malaspina D, Pepple J, Svrakic D, Markel PD, Meyer J, Zambuto CT, Schmitt K, Matise TC, Friedman JMH, Hampe C, Lee H, Shore D, Wynne D, Faraone SV, Tsuang MT, Cloninger CR. NIMH genetics initiative millennium schizophrenia consortium: Linkage analysis of African-American pedigrees. ACTA ACUST UNITED AC 1998. [DOI: 10.1002/(sici)1096-8628(19980710)81:4<282::aid-ajmg2>3.0.co;2-w] [Citation(s) in RCA: 206] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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17
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Schulz E, Fleischhaker C, Clement HW, Remschmidt H. Blood biogenic amines during clozapine treatment of early-onset schizophrenia. J Neural Transm (Vienna) 1998; 104:1077-89. [PMID: 9503259 DOI: 10.1007/bf01273320] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The aims of this investigation were to evaluate long-term and short-term effects of clozapine-treatment on plasma biogenic amines and psychopathology measures in adolescents with schizophrenia (DSM-III-R criteria). The long-term study was conducted in a study sample of 40 young patients (age 14-22 years) following a mean of 3.4 years of neuroleptic treatment. During the study, 20 patients received clozapine, and the other 20 patients were treated with standard neuroleptic medications. At the beginning of the open clinical trials, the patients had already been receiving clozapine treatment for 24 +/- 15 months. Assessment of the biochemical and psychopathological measures was performed on six occasions at consecutive 6-week intervals during maintenance treatment with clozapine or conventional neuroleptics. Blood levels of serotonin, 3-methoxy-4-hydroxy-phenylglycol (MHPG), norepinephrine, and epinephrine were significantly higher in clozapine-treated patients than in conventionally treated patients. During long-term treatment, higher serotonin levels were associated with significantly fewer negative symptoms of schizophrenia, whereas higher MHPG levels were correlated with less depression. The short-term effects of clozapine were assessed in a second and independent study sample. After failing on conventional neuroleptics in clinical trials lasting a mean of 1.6 years, 15 inpatients (aged 11-20 years) received clozapine. Weekly ratings of psychopathological symptoms using standard rating scales were performed in parallel to blood samplings for measurements of biogenic amines and serum levels of clozapine. These measures were obtained for 6 weeks during conventional neuroleptic treatment and for 6 weeks during the open-label clozapine trial. Serum levels of serotonin and plasma norepinephrine levels were significantly higher during treatment with clozapine than during pretreatment with typical neuroleptics. A comparison of plasma epinephrine levels in responders (n = 7) and nonresponders (n = 8) to clozapine revealed that response to clozapine can be predicted by epinephrine levels prior to initiation of treatment with clozapine (responders ranging from 32.2 to 90.3 pg/ml; nonresponders ranging from 92.5 to 473.5 pg/ml). Additionally, subjects who responded to clozapine showed increased mean plasma concentrations of MHPG and epinephrine during treatment with this drug in comparison to the levels measured during pretreatment with typical neuroleptic medication. Nonresponders to clozapine failed to show this increase. Finally, in responders to clozapine a negative linear relationship between negative symptoms of schizophrenia and the concentrations of plasma norepinephrine and serum serotonin were observed. In conclusion, our results demonstrate that plasma epinephrine levels prior to initiation of clozapine therapy predict response to this atypical neuroleptic. Our findings derived from short-term and maintenance treatment with clozapine suggest involvement of norepinephrine, epinephrine and serotonin in the therapeutic actions of the atypical neuroleptic clozapine.
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Affiliation(s)
- E Schulz
- Department of Child and Adolescent Psychiatry, Philipps-University, Marburg, Federal Republic of Germany
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18
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Jönsson E, Brené S, Geijer T, Terenius L, Tylec A, Persson ML, Sedvall G. A search for association between schizophrenia and dopamine-related alleles. Eur Arch Psychiatry Clin Neurosci 1996; 246:297-304. [PMID: 8908411 DOI: 10.1007/bf02189022] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Dopamine receptor dysfunction and altered tyrosine hydroxylase activity have both been implicated in the pathophysiology of schizophrenia. Schizophrenic patients and control subjects were examined for allele frequencies in the tyrosine hydroxylase and dopamine D2 and D4 receptor genes. No significant differences of allele or genotype frequencies were found between the two groups after adjustment for multiple comparisons. Neither were any significant relationships observed between allele frequencies and a number of clinical variables within the schizophrenic subsample. When no adjustment was made for multiple testing a few significant tendencies were obtained which warrant further research in extended patient and control materials. The results are compatible with the view that the tyrosine hydroxylase, dopamine receptor D2 and D4 gene polymorphisms examined are not of major importance in the aetiology or pathophysiology of schizophrenia.
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Affiliation(s)
- E Jönsson
- Department of Clinical Neuroscience, Karolinska Institute, Stockholm, Sweden
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