0000000000256343
AUTHOR
Marcella Rietschel
Heterozygous carriage of the alpha1-antitrypsin Pi*Z variant increases the risk to develop liver cirrhosis.
ObjectiveHomozygous alpha1-antitrypsin (AAT) deficiency increases the risk for developing cirrhosis, whereas the relevance of heterozygous carriage remains unclear. Hence, we evaluated the impact of the two most relevant AAT variants (‘Pi*Z’ and ‘Pi*S’), present in up to 10% of Caucasians, on subjects with non-alcoholic fatty liver disease (NAFLD) or alcohol misuse.DesignWe analysed multicentric case–control cohorts consisting of 1184 people with biopsy-proven NAFLD and of 2462 people with chronic alcohol misuse, both cohorts comprising cases with cirrhosis and controls without cirrhosis. Genotyping for the Pi*Z and Pi*S variants was performed.ResultsThe Pi*Z variant presented in 13.8% of p…
The Relationship Between Polygenic Risk Scores and Cognition in Schizophrenia
Abstract Background Cognitive impairment is a clinically important feature of schizophrenia. Polygenic risk score (PRS) methods have demonstrated genetic overlap between schizophrenia, bipolar disorder (BD), major depressive disorder (MDD), educational attainment (EA), and IQ, but very few studies have examined associations between these PRS and cognitive phenotypes within schizophrenia cases. Methods We combined genetic and cognitive data in 3034 schizophrenia cases from 11 samples using the general intelligence factor g as the primary measure of cognition. We used linear regression to examine the association between cognition and PRS for EA, IQ, schizophrenia, BD, and MDD. The results wer…
Trans-ancestral GWAS of alcohol dependence reveals common genetic underpinnings with psychiatric disorders
AbstractLiability to alcohol dependence (AD) is heritable, but little is known about its complex polygenic architecture or its genetic relationship with other disorders. To discover loci associated with AD and characterize the relationship between AD and other psychiatric and behavioral outcomes, we carried out the largest GWAS to date of DSM - IV diagnosed AD. Genome - wide data on 14,904 individuals with AD and 37,944 controls from 28 case / control and family - based studies were meta - analyzed, stratified by genetic ancestry (European, N = 46,568; African; N = 6,280). Independent, genome - wide significant effects of different ADH1B variants were identified in European (rs1229984; p = …
A genome screen for genes predisposing to bipolar affective disorder detects a new susceptibility locus on 8q
Bipolar affective disorder (BPAD), also known as manic depressive illness, is a severe psychiatric disorder characterized by episodes of mania and depression. It has a lifetime prevalence of approximately 1% in all human populations. In order to identify chromosomal regions containing genes that play a role in determining susceptibility to this psychiatric condition, we have conducted a complete genome screen with 382 markers (average marker spacing of 9.3 cM) in a sample of 75 BPAD families which were recruited through an explicit ascertainment scheme. Pedigrees were of German, Israeli and Italian origin, respectively. Parametric and non-parametric linkage analysis was performed. The highe…
Genetic contribution to alcohol dependence: Investigation of a heterogeneous german sample of individuals with alcohol dependence, chronic alcoholic pancreatitis, and alcohol-related cirrhosis
The present study investigated the genetic contribution to alcohol dependence (AD) using genome-wide association data from three German samples. These comprised patients with: (i) AD; (ii) chronic alcoholic pancreatitis (ACP); and (iii) alcohol-related liver cirrhosis (ALC). Single marker, gene-based, and pathway analyses were conducted. A significant association was detected for the ADH1B locus in a gene-based approach (puncorrected = 1.2 × 10-6; pcorrected = 0.020). This was driven by the AD subsample. No association with ADH1B was found in the combined ACP + ALC sample. On first inspection, this seems surprising, since ADH1B is a robustly replicated risk gene for AD and may therefore be …
Association Study of Nonsynonymous Single Nucleotide Polymorphisms in Schizophrenia
Genome-wide association studies using several hundred thousand anonymous markers present limited statistical power. Alternatively, association studies restricted to common nonsynonymous single nucleotide polymorphisms (nsSNPs) have the advantage of strongly reducing the multiple testing problem, while increasing the probability of testing functional single nucleotide polymorphisms (SNPs).We performed a case-control association study of common nsSNPs in Galician (northwest Spain) samples using the Affymetrix GeneChip Human 20k cSNP Kit, followed by a replication study of the more promising results. After quality control procedures, the discovery sample consisted of 5100 nsSNPs at minor allel…
Evaluation of linkage of bipolar affective disorder to chromosome 18 in a sample of 57 German families.
Previously reported linkage of bipolar affective disorder to DNA markers on chromosome 18 was reexamined in a large sample of German bipolar families. Twenty-three short tandem repeat markers were investigated in 57 families containing 103 individuals with bipolar I disorder (BPI), 26 with bipolar II disorder (BPII), nine with schizoaffective disorder of the bipolar type (SA/BP), and 38 individuals with recurrent unipolar depression (UPR). Evidence for linkage was tested with parametric and non-parametric methods under two definitions of the affected phenotype. Analysis of all 57 families revealed no robust evidence for linkage. Following previous reports we performed separate analyses afte…
Genome-wide association data provide further support for an association between 5-HTTLPR and major depressive disorder.
Abstract Background Dysfunctions of serotonergic neurotransmission are supposed to be involved in the pathogenesis of psychiatric disorders such as major depressive disorder (MDD). The concentration of serotonin (5-hydroxytryptamine, 5-HT) in the synaptic cleft is essentially regulated by the 5-HT transporter (5-HTT). A length polymorphism repeat in the 5-HTT promoter region, termed 5-HTTLPR, has been commonly investigated for an association with psychiatric disorders. Methods Genotyping of the 5-HTTLPR is time-consuming and technically challenging. Recently, a two-SNP haplotype was identified that tags the 5-HTTLPR at r 2 =0.775. This allows extraction of 5-HTTLPR genotype information from…
Mutationsanalyse des 5-HT1A-Rezeptor-Gens bei schizophrenen und affektiven Psychosen
Storungen im Serotoninstoffwechsel werden bei einer Vielzahl neuropsychiatrischer Erkrankungen (z. B. Angststorung, Depression, Schizophrenie, Alkoholismus, Migrane, Aggressives Verhalten, Suizidalitat, Tourette-Syndrom) beobachtet. Die Serotonin (5-Hydroxytryptamin, 5-HT) Rezeptoren konnen in mindestens drei Hauptgruppen unterteilt werden und zwar in 5-HTr, 5-HT2- und 5-HT3-Rezeptoren. Beim Menschen konnten bislang funf 5-HTrRezeptorsubtypen kloniert werden: der 5-HT1A, 5-HT1Dα, 5-HT1Dβ, 5-HT1E und der 5-HT1F Rezeptor (Ubersicht bei Shih et al. 1995). Der 5-HT1A ist der pharmakologisch am besten charakterisierte 5-HT1-Subtyp.
Genome-wide Association Study of Alcohol Dependence
Context Alcohol dependence is a serious and common public health problem. It is well established that genetic factors play a major role in the development of this disorder. Identification of genes that contribute to alcohol dependence will improve our understanding of the mechanisms that underlie this disorder. Objective To identify susceptibility genes for alcohol dependence through a genome-wide association study (GWAS) and a follow-up study in a population of German male inpatients with an early age at onset. Design The GWAS tested 524 396 single-nucleotide polymorphisms (SNPs). All SNPs with P −4 were subjected to the follow-up study. In addition, nominally significant SNPs from genes t…
Gene expression of neuregulin-1 isoforms in different brain regions of elderly schizophrenia patients
One important risk gene in schizophrenia is neuregulin-1 (NRG1), which is expressed in different isoforms in the brain. To determine if alterations of NRG1 are present in schizophrenia, we measured gene expression of NRG1 and its main isoforms as well as the impact of genetic variation of NRG1 in an exploratory study examining three brain regions instead of only one as published so far. In all, we examined post-mortem samples from 11 schizophrenia patients and eight normal subjects. We investigated gene expression of total NRG1 and isoforms I, II and III by real-time PCR in the prefrontal cortex (Brodmann areas 9 and 10) and right hippocampal tissue. For the genetic study, we genotyped the …
XRCC5 as a Risk Gene for Alcohol Dependence : Evidence from a Genome-Wide Gene-Set-Based Analysis and Follow-up Studies in Drosophila and Humans
Genetic factors play as large a role as environmental factors in the etiology of alcohol dependence. Although genome-wide association studies (GWAS) enable systematic searches for loci not hitherto implicated in the etiology of alcohol dependence, many true findings may be missed due to correction for multiple testing. The aim of the present study was to circumvent this limitation by searching for biological system-level differences, and then following up these findings in humans and animals. Gene-set based analysis of GWAS data from 1333 cases and 2168 controls identified 19 significantly associated gene-sets of which five could be replicated in an independent sample. Clustered in these ge…
A possible susceptibility locus for bipolar affective disorder in chromosomal region 10q25--q26.
In an attempt to identify susceptibility loci for bipolar affective disorder, we are currently conducting a systematic genome screen with highly polymorphic microsatellite markers at an average marker spacing of 10 cM in a series of 75 families, comprising 66 families from Germany, eight families from Israel, and one family from Italy. The families were ascertained through index cases with bipolar affective disorder. The distribution of diagnoses is as follows: 126 individuals with bipolar I disorder, 40 with bipolar II disorder, 14 with schizoaffective disorder of the bipolar type, 40 individuals with recurrent unipolar depression, 51 with a minor psychiatric diagnosis, and two individuals…
Genome-wide significant association between alcohol dependence and a variant in the ADH gene cluster
Alcohol dependence (AD) is an important contributory factor to the global burden of disease. The etiology of AD involves both environmental and genetic factors, and the disorder has a heritability of around 50%. The aim of the present study was to identify susceptibility genes for AD by performing a genome-wide association study (GWAS). The sample comprised 1333 male in-patients with severe AD according to the Diagnostic and Statistical Manual of Mental Disorders, 4th edition, and 2168 controls. These included 487 patients and 1358 controls from a previous GWAS study by our group. All individuals were of German descent. Single-marker tests and a polygenic score-based analysis to assess the …
Shared genetic risk between eating disorder- and substance-use-related phenotypes: Evidence from genome-wide association studies
AbstractEating disorders and substance use disorders frequently co-occur. Twin studies reveal shared genetic variance between liabilities to eating disorders and substance use, with the strongest associations between symptoms of bulimia nervosa (BN) and problem alcohol use (genetic correlation [rg], twin-based=0.23-0.53). We estimated the genetic correlation between eating disorder and substance use and disorder phenotypes using data from genome-wide association studies (GWAS). Four eating disorder phenotypes (anorexia nervosa [AN], AN with binge-eating, AN without binge-eating, and a BN factor score), and eight substance-use-related phenotypes (drinks per week, alcohol use disorder [AUD], …
Genetic relationship between five psychiatric disorders estimated from genome-wide SNPs
AM Vicente - Cross-Disorder Group of the Psychiatric Genomics Consortium Most psychiatric disorders are moderately to highly heritable. The degree to which genetic variation is unique to individual disorders or shared across disorders is unclear. To examine shared genetic etiology, we use genome-wide genotype data from the Psychiatric Genomics Consortium (PGC) for cases and controls in schizophrenia, bipolar disorder, major depressive disorder, autism spectrum disorders (ASD) and attention-deficit/hyperactivity disorder (ADHD). We apply univariate and bivariate methods for the estimation of genetic variation within and covariation between disorders. SNPs explained 17-29% of the variance in …
An integrated genome research network for studying the genetics of alcohol addiction
Alcohol drinking is highly prevalent in many cultures and contributes to the global burden of disease. In fact, it was shown that alcohol constitutes 3.2% of all worldwide deaths in the year 2006 and is linked to more than 60 diseases, including cancers, cardiovascular diseases, liver cirrhosis, neuropsychiatric disorders, injuries and foetal alcohol syndrome. Alcoholism, which has been proven to have a high genetic load, is one potentially fatal consequence of chronic heavy alcohol consumption, and may be regarded as one of the most prevalent neuropsychiatric diseases afflicting our society today. The aim of the integrated genome research network 'Genetics of Alcohol Addiction'-which is a …
Shared genetic etiology between alcohol dependence and major depressive disorder
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DeepWAS: Multivariate genotype-phenotype associations by directly integrating regulatory information using deep learning
Genome-wide association studies (GWAS) identify genetic variants associated with traits or diseases. GWAS never directly link variants to regulatory mechanisms. Instead, the functional annotation of variants is typically inferred by post hoc analyses. A specific class of deep learning-based methods allows for the prediction of regulatory effects per variant on several cell type-specific chromatin features. We here describe “DeepWAS”, a new approach that integrates these regulatory effect predictions of single variants into a multivariate GWAS setting. Thereby, single variants associated with a trait or disease are directly coupled to their impact on a chromatin feature in a cell type. Up to…
Psychiatric genome-wide association study analyses implicate neuronal, immune and histone pathways
G.B. and S.N. acknowledge funding support for this work from the National Institute for Health Research (NIHR) Mental Health Biomedical Research Centre at South London and Maudsley NHS Foundation Trust and King's College London. P.H.L. is supported by US National Institute of Mental Health (NIMH) grant K99MH101367. Genome-wide association studies (GWAS) of psychiatric disorders have identified multiple genetic associations with such disorders, but better methods are needed to derive the underlying biological mechanisms that these signals indicate. We sought to identify biological pathways in GWAS data from over 60,000 participants from the Psychiatric Genomics Consortium. We developed an an…
Applying polygenic risk scoring for psychiatric disorders to a large family with bipolar disorder and major depressive disorder
Psychiatric disorders are thought to have a complex genetic pathology consisting of interplay of common and rare variation. Traditionally, pedigrees are used to shed light on the latter only, while here we discuss the application of polygenic risk scores to also highlight patterns of common genetic risk. We analyze polygenic risk scores for psychiatric disorders in a large pedigree (n ~ 260) in which 30% of family members suffer from major depressive disorder or bipolar disorder. Studying patterns of assortative mating and anticipation, it appears increased polygenic risk is contributed by affected individuals who married into the family, resulting in an increasing genetic risk over generat…
Systematic screening for mutations in the promoter and the coding region of the 5-HT1A gene.
In the present study we sought to identify genetic variation in the 5-HT{sub 1A} receptor gene which through alteration of protein function or level of expression might contribute to the genetic predisposition to neuropsychiatric diseases. Genomic DNA samples from 159 unrelated subjects (including 45 schizophrenic, 46 bipolar affective, and 43 patients with Tourette`s syndrome, as well as 25 healthy controls) were investigated by single-strand conformation analysis. Overlapping PCR (polymerase chain reaction) fragments covered the whole coding sequence as well as the 5{prime} untranslated region of the 5-HT{sub 1A} gene. The region upstream to the coding sequence we investigated contains a …
Systematic screening for mutations in the human serotonin 1F receptor gene in patients with bipolar affective disorder and schizophrenia
Using single strand conformational analysis we screened the complete coding sequence of the serotonin 1F (5-HT{sub 1F}) receptor gene for the presence of DNA sequence variation in a sample of 137 unrelated individuals including 45 schizophrenic patients, 46 bipolar patients, as well as 46 healthy controls. We detected only three rare sequence variants which are characterized by single base pair substitutions, namely a silent T{r_arrow}A transversion in the third position of codon 261 (encoding isoleucine), a silent C{r_arrow}T transition in the third position of codon 176 (encoding histidine), and a C{r_arrow}T transition in position -78 upstream from the start codon. The lack of significan…
Systematic screening for mutations in the human serotonin-2A (5-HT2A) receptor gene: Identification of two naturally occurring receptor variants and association analysis in schizophrenia
A statistically significant association between a silent mutation (102T/C) in the serotonin-2A (5-HT2A) receptor gene and schizophrenia has recently been reported in a sample of Japanese patients and healthy controls. This finding suggests that genetic predisposition to schizophrenia may be affected by a functional 5-HT2A receptor variant that is in linkage disequilibrium with 102T/C. In the present study, we have sought to identify genetic variation in the 5-HT2A receptor gene by screening genomic DNA samples from 91 unrelated subjects comprising 45 patients with schizophrenia and 46 healthy controls by using single-strand conformation analysis. We have identified four nucleotide sequence …