Further evidence for association between ErbB4 and schizophrenia and influence on cognitive intermediate phenotypes in healthy controls.
Explore the source record for details and available documents.
Alleles↗
Biomedical subjects
R E Straub
Publications and source records attributed to R E Straub.
Dysbindin (DTNBP1, 6p22.3) is associated with childhood-onset psychosis and endophenotypes measured by the Premorbid Adjustment Scale (PAS).
Straub et al. (2002) recently identified the 6p22.3 gene dysbindin (DTNBP1) through positional cloning as a schizophrenia susceptibility gene. We studied a rare cohort of 102 children with onset of psychosis before age 13. Standardized ratings of early development, medication response, neuropsychological and cognitive performance, premorbid dysfunction and clinical follow-up were obtained. Fourteen SNPs were genotyped in the gene DTNBP1. Family-based pairwise and haplotype transmission disequilibrium test (TDT) analysis with the clinical phenotype, and quantitative transmission disequilibrium test (QTDT) explored endophenotype relationships. One SNP was associated with diagnosis (TDT p=.01). The QTDT analyses showed several significant relationships. Four adjacent SNPs were associated (p values=.0009-.003) with poor premorbid functioning. These findings support the hypothesis that this and other schizophrenia susceptibility genes contribute to early neurodevelopmental impairment.
Adolescent↗
GAD1 (2q31.1), which encodes glutamic acid decarboxylase (GAD67), is associated with childhood-onset schizophrenia and cortical gray matter volume loss.
Postmortem brain studies have shown deficits in the cortical gamma-aminobutyric acid (GABA) system in schizophrenic individuals. Expression studies have shown a decrease in the major GABA-synthesizing enzyme (glutamic acid decarboxylase (GAD67) mRNA levels in neurons in dorsolateral prefrontal cortex in schizophrenics relative to controls. In the present study, SNPs in and around the GAD1 gene, which encodes the protein GAD67, were tested on a rare, severely ill group of children and adolescents with childhood-onset schizophrenia (COS) (n=72), in a family-based association analysis. Compared to adult-onset samples, the COS sample has evidence for more salient familial, and perhaps genetic, risk factors for schizophrenia, as well as evidence for frontal cortical hypofunction, and greater decline in cortical gray matter volume on anatomic brain MRI scans during adolescence. We performed family-based TDT and haplotype association analyses of the clinical phenotype, as well as association analyses with endophenotypes using the QTDT program. Three adjacent SNPs in the 5' upstream region of GAD1 showed a positive pairwise association with illness in these families (P=0.022-0.057). Significant transmission distortion of 4-SNP haplotypes was also observed (P=0.003-0.008). Quantitative trait TDT analyses showed an intriguing association between several SNPs and increased rate of frontal gray matter loss. These observations, when taken together with the positive results reported recently in two independent adult-onset schizophrenia pedigree samples, suggest that the gene encoding GAD67 may be a common risk factor for schizophrenia.
5' Flanking Region↗
Clinical features of psychotic disorders and polymorphisms in HT2A, DRD2, DRD4, SLC6A3 (DAT1), and BDNF: a family based association study.
Schizophrenia is clinically heterogeneous and multidimensional, but it is not known whether this is due to etiological heterogeneity. Previous studies have not consistently reported association between any specific polymorphisms and clinical features of schizophrenia, and have primarily used case-control designs. We tested for the presence of association between clinical features and polymorphisms in the genes for the serotonin 2A receptor (HT2A), dopamine receptor types 2 and 4, dopamine transporter (SLC6A3), and brain-derived neurotrophic factor (BDNF). Two hundred seventy pedigrees were ascertained on the basis of having two or more members with schizophrenia or poor outcome schizoaffective disorder. Diagnoses were made using a structured interview based on the SCID. All patients were rated on the major symptoms of schizophrenia scale (MSSS), integrating clinical and course features throughout the course of illness. Factor analysis revealed positive, negative, and affective symptom factors. The program QTDT was used to implement a family-based test of association for quantitative traits, controlling for age and sex. We found suggestive evidence of association between the His452Tyr polymorphism in HT2A and affective symptoms (P = 0.02), the 172-bp allele of BDNF and negative symptoms (P = 0.04), and the 480-bp allele in SLC6A3 (= DAT1) and negative symptoms (P = 0.04). As total of 19 alleles were tested, we cannot rule out false positives. However, given prior evidence of involvement of the proteins encoded by these genes in psychopathology, our results suggest that more attention should be focused on the impact of these alleles on clinical features of schizophrenia.
Alleles↗
Expression analysis of neuregulin-1 in the dorsolateral prefrontal cortex in schizophrenia.
Genetic linkage and association have implicated neuregulin-1 (NRG-1) as a schizophrenia susceptibility gene. We measured mRNA expression levels of the three major isoforms of NRG-1 (ie type I, type II, and type III) in the postmortem dorsolateral prefrontal cortex (DLPFC) from matched patients and controls using real-time quantitative RT-PCR. Expression levels of three internal controls-GAPDH, cyclophilin, and beta-actin-were unchanged in schizophrenia, and there were no changes in the absolute levels of the NRG-1 isoforms. However, type I expression normalized by GAPDH levels was significantly increased in schizophrenia DLPFC (by 23%) and positively correlated with antipsychotic medication dosage. Type II/type I and type II/type III ratios were significantly decreased (18 and 23% respectively). There was no effect on the NRG-1 mRNA levels of genotype at two SNPs previously associated with schizophrenia, suggesting that these alleles are not functionally responsible for abnormal NRG-1 expression patterns in patients. Subtle abnormalities in the expression patterns of NRG-1 mRNA isoforms in DLPFC may be associated with schizophrenia.
Autopsy↗
Genome-wide scans of three independent sets of 90 Irish multiplex schizophrenia families and follow-up of selected regions in all families provides evidence for multiple susceptibility genes.
From our linkage study of Irish families with a high density of schizophrenia, we have previously reported evidence for susceptibility genes in regions 5q21-31, 6p24-21, 8p22-21, and 10p15-p11. In this report, we describe the cumulative results from independent genome scans of three a priori random subsets of 90 families each, and from multipoint analysis of all 270 families in ten regions. Of these ten regions, three (13q32, 18p11-q11, and 18q22-23) did not generate scores above the empirical baseline pairwise scan results, and one (6q13-26) generated a weak signal. Six other regions produced more positive pairwise and multipoint results. They showed the following maximum multipoint H-LOD (heterogeneity LOD) and NPL scores: 2p14-13: 0.89 (P = 0.06) and 2.08 (P = 0.02), 4q24-32: 1.84 (P = 0.007) and 1.67 (P = 0.03), 5q21-31: 2.88 (P= 0.0007), and 2.65 (P = 0.002), 6p25-24: 2.13 (P = 0.005) and 3.59 (P = 0.0005), 6p23: 2.42 (P = 0.001) and 3.07 (P = 0.001), 8p22-21: 1.57 (P = 0.01) and 2.56 (P = 0.005), 10p15-11: 2.04 (P = 0.005) and 1.78 (P = 0.03). The degree of 'internal replication' across subsets differed, with 5q, 6p, and 8p being most consistent and 2p and 10p being least consistent. On 6p, the data suggested the presence of two susceptibility genes, in 6p25-24 and 6p23-22. Very few families were positive on more than one region, and little correlation between regions was evident, suggesting substantial locus heterogeneity. The levels of statistical significance were modest, as expected from loci contributing to complex traits. However, our internal replications, when considered along with the positive results obtained in multiple other samples, suggests that most of these six regions are likely to contain genes that influence liability to schizophrenia.
Chromosome Mapping↗
Association of the tryptophan hydroxylase gene with smoking initiation but not progression to nicotine dependence.
We investigated the association between two markers in the seventh intron of the tryptophan hydroxylase gene (TPH C218A and C779A) in a population-based case control study of 780 genotyped subjects. As in prior studies, the two markers were in strong linkage disequilibrium. The phenotypes we studied were smoking initiation and progression to nicotine dependence. Allele, genotype, and estimated haplotype frequencies for each marker were highly significantly different for smoking initiation (P < 0.0004 for each comparison) and were nonsignificant for progression to nicotine dependence. An empirical test suggested that the positive results were unlikely to have resulted from population stratification. Our results are similar to those of Lerman et al. [2001: Am J Med Genet (Neuropsychiatr Genet) 105:000-000] in associating these TPH markers with a construct related to smoking initiation but dissimilar in the variable implicated. If these results replicate in other samples, the serotonergic system may be involved in the etiology of smoking initiation given the rate-limiting role of TPH in the biosynthesis of serotonin.
Alleles↗
Effect of COMT Val108/158 Met genotype on frontal lobe function and risk for schizophrenia.
Abnormalities of prefrontal cortical function are prominent features of schizophrenia and have been associated with genetic risk, suggesting that susceptibility genes for schizophrenia may impact on the molecular mechanisms of prefrontal function. A potential susceptibility mechanism involves regulation of prefrontal dopamine, which modulates the response of prefrontal neurons during working memory. We examined the relationship of a common functional polymorphism (Val(108/158) Met) in the catechol-O-methyltransferase (COMT) gene, which accounts for a 4-fold variation in enzyme activity and dopamine catabolism, with both prefrontally mediated cognition and prefrontal cortical physiology. In 175 patients with schizophrenia, 219 unaffected siblings, and 55 controls, COMT genotype was related in allele dosage fashion to performance on the Wisconsin Card Sorting Test of executive cognition and explained 4% of variance (P = 0.001) in frequency of perseverative errors. Consistent with other evidence that dopamine enhances prefrontal neuronal function, the load of the low-activity Met allele predicted enhanced cognitive performance. We then examined the effect of COMT genotype on prefrontal physiology during a working memory task in three separate subgroups (n = 11-16) assayed with functional MRI. Met allele load consistently predicted a more efficient physiological response in prefrontal cortex. Finally, in a family-based association analysis of 104 trios, we found a significant increase in transmission of the Val allele to the schizophrenic offspring. These data suggest that the COMT Val allele, because it increases prefrontal dopamine catabolism, impairs prefrontal cognition and physiology, and by this mechanism slightly increases risk for schizophrenia.
Adult↗
An association study of DRD5 with smoking initiation and progression to nicotine dependence.
A large body of genetic epidemiological data strongly implicate genetic factors in the etiology of smoking behavior. Polymorphisms of genes in the dopaminergic system are plausible functional candidate genes and a linkage and an association study suggested that the type 5 dopamine receptor gene (DRD5) may be etiologically involved. We investigated the association of four DRD5 polymorphisms with smoking initiation and progression to nicotine dependence in a population-based sample of over 900 subjects. For smoking initiation, there was no significant association with the four DRD5 markers we studied; however, maximum likelihood analyses suggested the presence of a haplotype protective against smoking initiation. For progression to nicotine dependence, there were no strongly significant associations with the four DRD5 markers or for the estimated haplotypes. These data are not consistent with a strong etiological role for DRD5 in the etiology of these complex smoking behaviors.
Adolescent↗
Analysis of epistasis in linked regions in the Irish study of high-density schizophrenia families.
Epistasis may be important in the etiology of schizophrenia. Analysis of epistasis has been important in the positional cloning of a gene involved in the etiology of type II diabetes mellitus. We investigated the importance of epistasis among six linked regions in 268 multiplex pedigrees in the Irish Study of High-Density Schizophrenia Families (ISHDSF) by computing pairwise correlations between nonparametric linkage scores for narrow, intermediate, and broad diagnostic definitions. The linked regions were on chromosomes 2, 4, 5, 6, 8, and 10. No correlation reached our a priori level of statistical significance. Using this statistical approach, we did not find evidence of important epistatic effects among these six regions in the ISHDSF.
Chromosomes, Human↗
Haplotypes of four novel single nucleotide polymorphisms in the nicotinic acetylcholine receptor beta2-subunit (CHRNB2) gene show no association with smoking initiation or nicotine dependence.
Several types of evidence, including experiments with mice that lack the nicotinic acetylcholine receptor beta2-subunit gene (CHRNB2), have suggested that a beta2-containing nicotinic receptor is necessary for at least some of the reinforcing properties of nicotine. However, sequence variations in CHRNB2 have not been reported, and its role in influencing human smoking behavior and nicotine dependence is not known. We screened most of the introns and exons and found five novel single nucleotide polymorphisms (SNPs). We tested four of these SNPs in three large, carefully selected samples: nonsmokers (n = 317) and regular smokers low levels of nicotine dependence (ND, n = 238), or smokers with high-ND (n = 317). None of the four polymorphisms we tested, nor their estimated haplotypes, were associated with smoking initiation or progression to nicotine dependence.
DNA↗
Multicenter linkage study of schizophrenia candidate regions on chromosomes 5q, 6q, 10p, and 13q: schizophrenia linkage collaborative group III.
Schizophrenia candidate regions 33-51 cM in length on chromosomes 5q, 6q, 10p, and 13q were investigated for genetic linkage with mapped markers with an average spacing of 5.64 cM. We studied 734 informative multiplex pedigrees (824 independent affected sibling pairs [ASPs], or 1,003 ASPs when all possible pairs are counted), which were collected in eight centers. Cases with diagnoses of schizophrenia or schizoaffective disorder (DSM-IIIR criteria) were considered affected (n=1,937). Data were analyzed with multipoint methods, including nonparametric linkage (NPL), ASP analysis using the possible-triangle method, and logistic-regression analysis of identity-by-descent (IBD) sharing in ASPs with sample as a covariate, in a test for intersample heterogeneity and for linkage with allowance for intersample heterogeneity. The data most supportive for linkage to schizophrenia were from chromosome 6q; logistic-regression analysis of linkage allowing for intersample heterogeneity produced an empirical P value <.0002 with, or P=.0004 without, inclusion of the sample that produced the first positive report in this region; the maximum NPL score in this region was 2.47 (P=.0046), the maximum LOD score (MLS) from ASP analysis was 3.10 (empirical P=.0036), and there was significant evidence for intersample heterogeneity (empirical P=.0038). More-modest support for linkage was observed for chromosome 10p, with logistic-regression analysis of linkage producing an empirical P=. 045 and with significant evidence for intersample heterogeneity (empirical P=.0096).
Chromosome Mapping↗
SETA is a multifunctional adapter protein with three SH3 domains that binds Grb2, Cbl, and the novel SB1 proteins.
Expression of the src homology 3 (SH3)-encoding, expressed in tumorigenic astrocytes (SETA) gene is associated with astrocyte transformation in culture and tumors in the adult brain. SETA binds to the apoptosis regulator apoptosis-linked gene 2 (ALG-2) interacting protein 1 (AIP1), and modulates apoptosis in astrocytes. The predicted protein structure of SETA revealed two SH3 domains, while related proteins were reported to have three. Here we report the identification of an additional SH3 domain N-terminal to the previously identified SETA sequence. Yeast two-hybrid screening of a p53(-/-) astrocyte cDNA library with this SH3 domain identified a novel gene, SETA binding protein 1 (SB1), with 55% amino acid identity to the renal tumor antigen, NY-REN-45. In vitro confrontation and co-immunoprecipitation experiments confirmed the binding of SB1 to SETA. Evidence that SETA binds to the CD2 protein, the proto-oncogene c-Cbl, and the signal transduction molecule Grb2, and can dimerize via its C-terminal coiled coil (CC) domain is also presented.
Adaptor Proteins, Signal Transducing↗
The trimmed-haplotype test for linkage disequilibrium.
Single-marker linkage-disequilibrium (LD) methods cannot fully describe disequilibrium in an entire chromosomal region surrounding a disease allele. With the advent of myriad tightly linked microsatellite markers, we have an opportunity to extend LD analysis from single markers to multiple-marker haplotypes. Haplotype analysis has increased statistical power to disclose the presence of a disease locus in situations where it correctly reflects the historical process involved. For maximum efficiency, evidence of LD ought to come not just from a single haplotype, which may well be rare, but in addition from many similar haplotypes that could have descended from the same ancestral founder but have been trimmed in succeeding generations. We present such an analysis, called the "trimmed-haplotype method." We focus on chromosomal regions that are small enough that disequilibrium in significant portions of them may have been preserved in some pedigrees and yet that contain enough markers to minimize coincidental occurrence of the haplotype in the absence of a disease allele: perhaps regions 1-2 cM in length. In general, we could have no idea what haplotype an ancestral founder carried generations ago, nor do we usually have a precise chromosomal location for the disease-susceptibility locus. Therefore, we must search through all possible haplotypes surrounding multiple locations. Since such repeated testing obliterates the sampling distribution of the test, we employ bootstrap methods to calculate significance levels. Trimmed-haplotype analysis is performed on family data in which genotypes have been assembled into haplotypes. It can be applied either to conventional parent-affected-offspring triads or to multiplex pedigrees. We present a method for summarizing the LD evidence, in any pedigree, that can be employed in trimmed-haplotype analysis as well as in other methods.
Alleles↗
Clinical features of schizophrenia and linkage to chromosomes 5q, 6p, 8p, and 10p in the Irish Study of High-Density Schizophrenia Families.
OBJECTIVE: Schizophrenia is clinically heterogeneous. Recent linkage studies suggest that multiple genes are important in the etiology of schizophrenia. The authors examined the hypothesis of whether the clinical variability in schizophrenia is due to genetic heterogeneity. METHOD: Using data from the Irish Study of High-Density Schizophrenia Families (N=265 pedigrees; N=1,408 individuals), the authors attempted to predict, from major symptoms and signs of psychosis, evidence for linkage within families for schizophrenia-related disorders to chromosomal regions 5q21-5q31, 6p24-6p22, 8p22-8p21, and 10p15-10p11. RESULTS: No substantial evidence was found for associations between clinical features of schizophrenia and linkage to chromosomes 5q, 6p, or 10p. However, affected individuals from families with evidence for linkage to 8p had significantly more affective deterioration, poorer outcome, more thought disorder, and fewer depressive symptoms than affected individuals from the other families in the study. CONCLUSIONS: These results raise the possibility that the putative susceptibility gene for schizophrenia localized in the 8p22-8p21 region may predispose individuals to the core dementia-praecox syndrome described by Kraepelin more than 100 years ago.
Chromosomes, Human, Pair 10↗
Sibling correlation of deficit syndrome in the Irish study of high-density schizophrenia families.
OBJECTIVE: The deficit syndrome is a subtype of schizophrenia characterized by primary and enduring negative features of psychopathology. It appears to reflect a distinct subtype within the syndrome of schizophrenia. Little is known about the familial or genetic aspects of the deficit syndrome. The purpose of this study was to determine whether deficit versus nondeficit subtypes are correlated in sibling pairs affected with schizophrenia. METHOD: The present study was based on the Irish Study of High-Density Schizophrenia Families. From the earlier study the authors selected a subset of patients who were members of sibling pairs in which both siblings had been diagnosed with "core" schizophrenia, which included schizophrenia, simple schizophrenia, and schizoaffective disorder with poor outcome. The Schedule for the Deficit Syndrome was used to make deficit versus nondeficit diagnoses, which were based on chart examinations by reviewers blind to sibling status. This method resulted in 65 patients being diagnosed with the deficit syndrome and 401 patients diagnosed as nondeficit (prevalence=13.9%). This group included 347 full sibling pairs, which were analyzed for resemblance with respect to deficit versus nondeficit subtype by means of logistic regression. RESULTS: Deficit versus nondeficit subtypes were significantly correlated in sibling pairs concordant for core schizophrenia. CONCLUSIONS: Familial factors contribute significantly to whether a person has the deficit subtype of schizophrenia. This familial contribution could be genetic or environmental.
Adult↗
HLA and schizophrenia: refutation of reported associations with A9 (A23/A24), DR4, and DQbeta1*0602.
The aim of this study was to test previous hypotheses of association between schizophrenia and human leukocyte antigen (HLA) specificities A9 (A23/24), DR4, and allele DQbeta1*0602. Using sequence-specific oligonucleotide probes, 256 familial schizophrenic patients and 261 unrelated controls were genotyped at polymorphisms for HLA-A, DRbeta1, and DQbeta1 loci. No significant (p < 0.05) differences in the allele frequencies between schizophrenics and controls were found, either when examining the sample as a whole or when subdivided by clinical subtype or gender. The present data do not support association between these HLA specificities and schizophrenia, and our review of previous studies suggests that reported associations may well be false positive results.
Case-Control Studies↗
Schizophrenia and HLA: No association with PCR-SSOP typed classical loci in a large Irish familial sample.
Susceptibility to autoimmunity is strongly influence by genes clustered in the MHC region, particularly class I and class II antigens. It has been proposed that there is an immune component in the aetiology of schizophrenia, and the distribution of human leukocyte antigens (HLA) in schizophrenic patients and controls has been investigated in numerous studies. Positive associations have been reported between schizophrenia and the HLA-A1, A2, A9, B5, Cw4, and DR8 and negative associations with HLA-DR4 and HLA-DQbeta*0602. Small sample size, variable diagnostic methodology, unreliable laboratory and statistical procedures, and possible mismatching of cases and controls may have contributed to a lack of consistency of results to date. Therefore, in this investigation we used a large and carefully diagnosed homogeneous Irish familial schizophrenic sample compared with ethnically matched controls. All alleles were determined using polymerase chain reaction amplification followed by short specific oligoprobes. We found no evidence of association with 80 HLA alleles (some previously not examined) from 4 genes. Our data therefore do not support the involvement of these classical HLA loci in the aetiology of schizophrenia at least in these Irish families. The remaining classical HLA loci (HLA-B and HLA-C) should be typed when reliable DNA-based methods become available.
Alleles↗