We conducted a genome-wide association study (GWAS) and a follow-up study of bipolar disorder (BD), a common neuropsychiatric disorder. In the GWAS, we investigated 499,494 autosomal and 12,484 X-chromosomal SNPs in 682 patients with BD and in 1300 controls. In the first follow-up step, we tested the most significant 48 SNPs in 1729 patients with BD and in 2313 controls. Eight SNPs showed nominally significant association with BD and were introduced to a meta-analysis of the GWAS and the first follow-up samples. Genetic variation in the neurocan gene (NCAN) showed genome-wide significant association with BD in 2411 patients and 3613 controls (rs1064395, p = 3.02 × 10−8; odds ratio = 1.31). In a second follow-up step, we replicated this finding in independent samples of BD, totaling 6030 patients and 31,749 controls (p = 2.74 × 10−4; odds ratio = 1.12). The combined analysis of all study samples yielded a p value of 2.14 × 10−9 (odds ratio = 1.17). Our results provide evidence that rs1064395 is a common risk factor for BD. NCAN encodes neurocan, an extracellular matrix glycoprotein, which is thought to be involved in cell adhesion and migration. We found that expression in mice is localized within cortical and hippocampal areas. These areas are involved in cognition and emotion regulation and have previously been implicated in BD by neuropsychological, neuroimaging, and postmortem studies. We conducted a genome-wide association study (GWAS) and a follow-up study of bipolar disorder (BD), a common neuropsychiatric disorder. In the GWAS, we investigated 499,494 autosomal and 12,484 X-chromosomal SNPs in 682 patients with BD and in 1300 controls. In the first follow-up step, we tested the most significant 48 SNPs in 1729 patients with BD and in 2313 controls. Eight SNPs showed nominally significant association with BD and were introduced to a meta-analysis of the GWAS and the first follow-up samples. Genetic variation in the neurocan gene (NCAN) showed genome-wide significant association with BD in 2411 patients and 3613 controls (rs1064395, p = 3.02 × 10−8; odds ratio = 1.31). In a second follow-up step, we replicated this finding in independent samples of BD, totaling 6030 patients and 31,749 controls (p = 2.74 × 10−4; odds ratio = 1.12). The combined analysis of all study samples yielded a p value of 2.14 × 10−9 (odds ratio = 1.17). Our results provide evidence that rs1064395 is a common risk factor for BD. NCAN encodes neurocan, an extracellular matrix glycoprotein, which is thought to be involved in cell adhesion and migration. We found that expression in mice is localized within cortical and hippocampal areas. These areas are involved in cognition and emotion regulation and have previously been implicated in BD by neuropsychological, neuroimaging, and postmortem studies. Bipolar disorder (BD [MIM 125480]) is a highly heritable disorder of mood, characterized by recurrent episodes of mania and depression that are often accompanied by behavioral and cognitive disturbances. Linkage and candidate-gene studies were the only available approaches for unraveling the genetic underpinnings of the disorder until the recent introduction of genome-wide association studies (GWAS). To date, six GWAS using common SNPs have been published.1Wellcome Trust Case Control ConsortiumGenome-wide association study of 14,000 cases of seven common diseases and 3,000 shared controls.Nature. 2007; 447: 661-678Crossref PubMed Scopus (7343) Google Scholar, 2Baum A.E. Akula N. Cabanero M. Cardona I. Corona W. Klemens B. Schulze T.G. Cichon S. Rietschel M. Nöthen M.M. et al.A genome-wide association study implicates diacylglycerol kinase eta (DGKH) and several other genes in the etiology of bipolar disorder.Mol. Psychiatry. 2008; 13: 197-207Crossref PubMed Scopus (507) Google Scholar, 3Sklar P. Smoller J.W. Fan J. Ferreira M.A. Perlis R.H. Chambert K. Nimgaonkar V.L. McQueen M.B. Faraone S.V. Kirby A. et al.Whole-genome association study of bipolar disorder.Mol. Psychiatry. 2008; 13: 558-569Crossref PubMed Scopus (520) Google Scholar, 4Ferreira M.A. O'Donovan M.C. Meng Y.A. Jones I.R. Ruderfer D.M. Jones L. Fan J. Kirov G. Perlis R.H. Green E.K. et al.Wellcome Trust Case Control ConsortiumCollaborative genome-wide association analysis supports a role for ANK3 and CACNA1C in bipolar disorder.Nat. Genet. 2008; 40: 1056-1058Crossref PubMed Scopus (888) Google Scholar, 5Scott L.J. Muglia P. Kong X.Q. Guan W. Flickinger M. Upmanyu R. Tozzi F. Li J.Z. Burmeister M. Absher D. et al.Genome-wide association and meta-analysis of bipolar disorder in individuals of European ancestry.Proc. Natl. Acad. Sci. USA. 2009; 106: 7501-7506Crossref PubMed Scopus (218) Google Scholar, 6Smith E.N. Bloss C.S. Badner J.A. Barrett T. Belmonte P.L. Berrettini W. Byerley W. Coryell W. Craig D. Edenberg H.J. et al.Genome-wide association study of bipolar disorder in European American and African American individuals.Mol. Psychiatry. 2009; 14: 755-763Crossref PubMed Scopus (262) Google Scholar Although there has been only limited consistency across studies regarding the top associated genomic regions,1Wellcome Trust Case Control ConsortiumGenome-wide association study of 14,000 cases of seven common diseases and 3,000 shared controls.Nature. 2007; 447: 661-678Crossref PubMed Scopus (7343) Google Scholar, 2Baum A.E. Akula N. Cabanero M. Cardona I. Corona W. Klemens B. Schulze T.G. Cichon S. Rietschel M. Nöthen M.M. et al.A genome-wide association study implicates diacylglycerol kinase eta (DGKH) and several other genes in the etiology of bipolar disorder.Mol. Psychiatry. 2008; 13: 197-207Crossref PubMed Scopus (507) Google Scholar, 3Sklar P. Smoller J.W. Fan J. Ferreira M.A. Perlis R.H. Chambert K. Nimgaonkar V.L. McQueen M.B. Faraone S.V. Kirby A. et al.Whole-genome association study of bipolar disorder.Mol. Psychiatry. 2008; 13: 558-569Crossref PubMed Scopus (520) Google Scholar, 5Scott L.J. Muglia P. Kong X.Q. Guan W. Flickinger M. Upmanyu R. Tozzi F. Li J.Z. Burmeister M. Absher D. et al.Genome-wide association and meta-analysis of bipolar disorder in individuals of European ancestry.Proc. Natl. Acad. Sci. USA. 2009; 106: 7501-7506Crossref PubMed Scopus (218) Google Scholar, 6Smith E.N. Bloss C.S. Badner J.A. Barrett T. Belmonte P.L. Berrettini W. Byerley W. Coryell W. Craig D. Edenberg H.J. et al.Genome-wide association study of bipolar disorder in European American and African American individuals.Mol. Psychiatry. 2009; 14: 755-763Crossref PubMed Scopus (262) Google Scholar meta-analyses of some of these studies have revealed common association signals: a meta-analysis7Baum A.E. Hamshere M. Green E. Cichon S. Rietschel M. Noethen M.M. Craddock N. McMahon F.J. Meta-analysis of two genome-wide association studies of bipolar disorder reveals important points of agreement.Mol. Psychiatry. 2008; 13: 466-467Crossref PubMed Scopus (88) Google Scholar of the Baum et al.2Baum A.E. Akula N. Cabanero M. Cardona I. Corona W. Klemens B. Schulze T.G. Cichon S. Rietschel M. Nöthen M.M. et al.A genome-wide association study implicates diacylglycerol kinase eta (DGKH) and several other genes in the etiology of bipolar disorder.Mol. Psychiatry. 2008; 13: 197-207Crossref PubMed Scopus (507) Google Scholar and Wellcome Trust Case Control Consortium (WTCCC)1Wellcome Trust Case Control ConsortiumGenome-wide association study of 14,000 cases of seven common diseases and 3,000 shared controls.Nature. 2007; 447: 661-678Crossref PubMed Scopus (7343) Google Scholar data sets found evidence of a consistent association between BD and variants in the genes JAM3 (MIM 606871) (rs10791345, p = 1 × 10−6) and SLC39A3 (MIM 612168) (rs4806874, p = 5 × 10−6). A combined analysis4Ferreira M.A. O'Donovan M.C. Meng Y.A. Jones I.R. Ruderfer D.M. Jones L. Fan J. Kirov G. Perlis R.H. Green E.K. et al.Wellcome Trust Case Control ConsortiumCollaborative genome-wide association analysis supports a role for ANK3 and CACNA1C in bipolar disorder.Nat. Genet. 2008; 40: 1056-1058Crossref PubMed Scopus (888) Google Scholar of the Sklar et al.3Sklar P. Smoller J.W. Fan J. Ferreira M.A. Perlis R.H. Chambert K. Nimgaonkar V.L. McQueen M.B. Faraone S.V. Kirby A. et al.Whole-genome association study of bipolar disorder.Mol. Psychiatry. 2008; 13: 558-569Crossref PubMed Scopus (520) Google Scholar and WTCCC1Wellcome Trust Case Control ConsortiumGenome-wide association study of 14,000 cases of seven common diseases and 3,000 shared controls.Nature. 2007; 447: 661-678Crossref PubMed Scopus (7343) Google Scholar studies, which included a total of 4387 patients and 6209 controls, identified a genome-wide significant association signal for BD in ANK3 (MIM 600465) (rs10994336, p = 9.1 × 10−9). The second strongest finding was for rs1006737 in CACNA1C (MIM 114205) (p = 7 × 10−8). Further independent support for ANK3 rs10994336 has recently been found by Schulze et al.8Schulze T.G. Detera-Wadleigh S.D. Akula N. Gupta A. Kassem L. Steele J. Pearl J. Strohmaier J. Breuer R. Schwarz M. et al.NIMH Genetics Initiative Bipolar Disorder ConsortiumTwo variants in Ankyrin 3 (ANK3) are independent genetic risk factors for bipolar disorder.Mol. Psychiatry. 2009; 14: 487-491Crossref PubMed Scopus (134) Google Scholar in samples from Germany (overlapping with samples used in the present GWAS; see Table S1 available online) and the USA; the same study8Schulze T.G. Detera-Wadleigh S.D. Akula N. Gupta A. Kassem L. Steele J. Pearl J. Strohmaier J. Breuer R. Schwarz M. et al.NIMH Genetics Initiative Bipolar Disorder ConsortiumTwo variants in Ankyrin 3 (ANK3) are independent genetic risk factors for bipolar disorder.Mol. Psychiatry. 2009; 14: 487-491Crossref PubMed Scopus (134) Google Scholar reported evidence for allelic heterogeneity at the ANK3 locus. Although GWAS studies of BD have identified a number of potentially relevant genetic variants, the widely acknowledged formal threshold for genome-wide significance of p = 5 × 10−8 has been surpassed only for variation in ANK3 so far. In the present study, we performed a GWAS and a two-step follow-up study of clinically well-characterized BD samples from Europe, the USA, and Australia. The GWAS and replication I included only European BD samples and produced genome-wide significant evidence for association in the neurocan gene (NCAN [MIM 600826]) (rs1064395, p = 3.02 × 10−8; odds ratio [OR] = 1.31). We then replicated this finding in large, independent samples from Europe, the USA, and Australia (p = 2.74 × 10−4; OR = 1.12). A combined analysis across all samples, adding up to 8441 patients with BD and 35,362 controls, gave p = 2.14 × 10−9 (OR = 1.17). Further support for an involvement of this gene in BD comes from our observation that Ncan expression in mice is localized within cortical and hippocampal areas. These regions have previously been implicated in BD by neuropsychological, neuroimaging, and postmortem studies. In the following text, we provide a phenotype description of the samples used in each step of our study (GWAS, replication I, replication II), specifications of the SNP genotyping, and the quality control (QC) measures applied to the raw genotyping data: The patients included in our GWAS and replication I step received a lifetime diagnosis of BD according to the DSM-IV9American Psychiatric Association (APA)Diagnostic and Statistical Manual of Mental Disorders.Fourth Edition. American Pychiatric Association, Washington, D.C.1994Google Scholar criteria on the basis of a consensus best-estimate procedure10Leckman J.F. Sholomskas D. Thompson W.D. Belanger A. Weissman M.M. Best estimate of lifetime psychiatric diagnosis: a methodological study.Arch. Gen. Psychiatry. 1982; 39: 879-883Crossref PubMed Scopus (1254) Google Scholar and structured diagnostic interviews.11Spitzer R.L. Williams J.B. Gibbon M. First M.B. The Structured Clinical Interview for DSM-III-R (SCID). I: History, rationale, and description.Arch. Gen. Psychiatry. 1992; 49: 624-629Crossref PubMed Scopus (3284) Google Scholar, 12Farmer A.E. Wessely S. Castle D. McGuffin P. Methodological issues in using a polydiagnostic approach to define psychotic illness.Br. J. Psychiatry. 1992; 161: 824-830Crossref PubMed Scopus (45) Google Scholar Protocols and procedures were approved by the local ethics committees. Written informed consent was obtained from all patients and controls. They were recruited from consecutive admissions to psychiatric inpatient units at (1) The Central Institute of Mental Health, Mannheim (n = 1081), (2) Department of Psychiatry, Poznan University of Medical Sciences, Poznan, Poland (n = 446), (3) Alexandru Obregia Clinical Psychiatric Hospital, Bucharest, Romania (n = 237), (4) Civil Hospital Carlos Haya, Málaga, Spain (n = 298), (5) Russian State Medical University, Moscow (n = 329), and (6) Kosevo Hospital, Sarajevo, Bosnia and Herzegovina (n = 125). All controls of replication I were also recruited by the abovementioned institutions. All GWAS controls were drawn from three population-based epidemiological studies: (1) PopGen13Krawczak M. Nikolaus S. von Eberstein H. Croucher P.J. El Mokhtari N.E. Schreiber S. PopGen: population-based recruitment of patients and controls for the analysis of complex genotype-phenotype relationships.Community Genet. 2006; 9: 55-61Crossref PubMed Scopus (263) Google Scholar (n = 490), (2) KORA14Wichmann H.E. Gieger C. Illig T. MONICA/KORA Study GroupKORA-gen—resource for population genetics, controls and a broad spectrum of disease phenotypes.Gesundheitswesen. 2005; 67: S26-S30Crossref PubMed Scopus (334) Google Scholar (n = 488), and (3) the Heinz Nixdorf Recall Study (Risk Factors, Evaluation of Coronary Calcification, and Lifestyle) (HNR,15Schmermund A. Möhlenkamp S. Stang A. Grönemeyer D. Seibel R. Hirche H. Mann K. Siffert W. Lauterbach K. Siegrist J. et al.Assessment of clinically silent atherosclerotic disease and established and novel risk factors for predicting myocardial infarction and cardiac death in healthy middle-aged subjects: rationale and design of the Heinz Nixdorf RECALL Study. Risk Factors, Evaluation of Coronary Calcium and Lifestyle.Am. Heart J. 2002; 144: 212-218Abstract Full Text Full Text PDF PubMed Scopus (411) Google Scholar n = 383). Ancestry was assigned to patients and controls on the basis of self-reported ancestry. More detailed sample descriptions are given in Table 1.Table 1Descriptive Data for Patients with Bipolar Disorder and Controls Following Quality ControlSampleAncestryN PatientsN ControlsBD1 (%)BD2 (%)SAB (%)BD-NOS (%)MaD (%)DiagnosisInterviewControls Screened?GWASGermany IGerman6821300679 (99.56)2 (0.29)1 (0.15)00DSM-IVSADS-L, SCIDnoReplication IGermany IIGerman361755138 (38.23)93 (25.76)130 (36.01)00DSM-IVSADS-L, SCIDnoPolandPolish411504323 (78.59)88 (21.41)000DSM-IVSCIDnoSpainSpanish297391290 (97.64)7 (2.36)000DSM-IVSADS-LnoRussiaRussian326329324 (96.38)2 (0.61)000DSM-IVSCIDnoRomaniaRomanian227221227 (100)0000DSM-IVSCIDyesBosnia and Herzegovina / SerbiaBosnian / Serbian107113107 (100)0000DSM-IVSCIDnoTotal24113613208819213100Replication IIGAIN-EA / TGEN1European218914342062 (94.20)0127 (5.80)00DSM-III, DSM-IV,RDCDIGSyesWTCCC-BD / Exp. Ref. Grp.British186814,3111594 (85.33)134 (7.17)98 (5.25)38 (2.03)4 (0.21)RDCSCANnoGermany IIIGerman497857376 (75.65)88 (17.71)2 (0.04)31 (6.24)0DSM-IVAMDP, CID-S, SADS-L, SCIDyesFranceFrench4711758360 (76.43)99 (21.02)012 (2.55)0DSM-IVDIGSnoIcelandIcelandic42211,487323 (76.54)72 (17.06)027 (6.40)0DSM-III, DSM-IV,ICD10, RDCCID-I, SADS-LnoAustraliaEuropean3801530291 (76.58)87 (22.89)1 (0.26)1 (0.26)0DSM-IVDIGS, FIGS, SCIDnoNorwayNorwegian203372128 (63.05)65 (32.02)010 (4.93)0DSM-IVSCID, PRIME-MDyesTotal603031,74951345452281194Grand Total844135,36272227373591194Patients received diagnoses according to the indicated diagnostic criteria and interviews. Protocols and procedures were approved by the local Ethics Committees. Written informed consent was obtained from all patients and controls. Ancestry was assigned to patients and controls on the basis of self-reported ancestry. The samples from Bosnia and Herzegovina / Serbia were merged due to the small number of subjects. The Expanded Reference Group for the WTCCC-BD sample comprised the 1958 British Birth Cohort controls, the UK Blood Services controls supplemented by the other 6 disease sets (coronary artery disease, Crohn's disease, hypertension, rheumatoid arthritis, type 1 and type 2 diabetes) as defined by the WTCCC (2007).1Wellcome Trust Case Control ConsortiumGenome-wide association study of 14,000 cases of seven common diseases and 3,000 shared controls.Nature. 2007; 447: 661-678Crossref PubMed Scopus (7343) Google ScholarThe following abbreviations are used: AMDP, Association for Methodology and Documentation in Psychiatry;31The AMDP SystemThe AMDP-System Association of Methodology and Documentation in Psychiatry. Manual For the Assessment and Documentation of Psychopathology. Springer, Berlin1982Google Scholar BD1, bipolar disorder type 1; BD2, bipolar disorder type 2; BD-NOS, bipolar disorder not otherwise specified; CID-I, Composite International Diagnostic Interview;32Peters L. Andrews G. Procedural validity of the computerized version of the Composite International Diagnostic Interview (CIDI-Auto) in the anxiety disorders.Psychol. Med. 1995; 25: 1269-1280Crossref PubMed Scopus (142) Google Scholar, 33Wittchen H.U. Zhao S. Abelson J.M. Abelson J.L. Kessler R.C. Reliability and procedural validity of UM-CIDI DSM-III-R phobic disorders.Psychol. Med. 1996; 26: 1169-1177Crossref PubMed Google Scholar CID-S, Composite International Diagnostic Screener;34Wittchen H.U. Höfler M. Gander F. Pfister H. Storz S. Üstün T.B. Müller N. Kessler R.C. Screening for mental disorders: performance of the Composite International Diagnostic-Screener (CID-S).Int. J. Methods Psychiatr. Res. 1999; 8: 59-70Crossref Scopus (117) Google Scholar DIGS, Diagnostic Interview for Genetic Studies;35Nurnberger Jr., J.I. Blehar M.C. Kaufmann C.A. York-Cooler C. Simpson S.G. Harkavy-Friedman J. Severe J.B. Malaspina D. Reich T. Diagnostic interview for genetic studies. Rationale, unique features, and training.Arch Gen Psychiatry. 1994; 51 (discussion 863–864): 849-859Crossref PubMed Scopus (1722) Google Scholar DSM-III / DSM-IV, Diagnostic and Statistical Manual of Mental Disorders;9American Psychiatric Association (APA)Diagnostic and Statistical Manual of Mental Disorders.Fourth Edition. American Pychiatric Association, Washington, D.C.1994Google Scholar Exp. Ref. Grp., Expanded Reference Group (11,373 controls);1Wellcome Trust Case Control ConsortiumGenome-wide association study of 14,000 cases of seven common diseases and 3,000 shared controls.Nature. 2007; 447: 661-678Crossref PubMed Scopus (7343) Google Scholar FIGS, Family Interview for Genetic Studies;36Maxwell M.E. Family Interview for Genetic Studies (FIGS): Manual For FIGS. Clinical Neurogenetics Branch. Intramural Research Program. National Institute of Mental Health, Bethesda, MD1992Google Scholar GAIN-EA, BD sample with European ancestry from the Genetic Association Information Network (1001 patients and 1033 controls);6Smith E.N. Bloss C.S. Badner J.A. Barrett T. Belmonte P.L. Berrettini W. Byerley W. Coryell W. Craig D. Edenberg H.J. et al.Genome-wide association study of bipolar disorder in European American and African American individuals.Mol. Psychiatry. 2009; 14: 755-763Crossref PubMed Scopus (262) Google Scholar ICD10, International Statistical Classification of Diseases and Related Health Problems;37World Health Organization (WHO)The ICD 10 Classification of Mental and Behavioural Disorders. Clinical Descriptions and Diagnostic Guidelines. WHO, Geneva1992Google Scholar MaD, Manic disorder according to RDC; N, number of subjects; PRIME-MD, Primary Care Evaluation of Mental Disorders;38Spitzer R.L. Williams J.B. Kroenke K. Linzer M. deGruy 3rd, F.V. Hahn S.R. Brody D. Johnson J.G. Utility of a new procedure for diagnosing mental disorders in primary care. The PRIME-MD 1000 study.JAMA. 1994; 272: 1749-1756Crossref PubMed Scopus (2306) Google Scholar RDC, Research Diagnostic Criteria;39Spitzer R.L. Endicott J. Robins E. Research diagnostic criteria: rationale and reliability.Arch. Gen. Psychiatry. 1978; 35: 773-782Crossref PubMed Scopus (5035) Google Scholar SAB, schizoaffective disorder (bipolar type); SADS-L, Schedule for Affective Disorders and Schizophrenia;40Endicott J. Spitzer R.L. A diagnostic interview: the schedule for affective disorders and schizophrenia.Arch. Gen. Psychiatry. 1978; 35: 837-844Crossref PubMed Scopus (4718) Google Scholar SCAN, Schedules for Clinical Assessment in Neuropsychiatry;41Wing J.K. Babor T. Brugha T. Burke J. Cooper J.E. Giel R. Jablenski A. Regier D. Sartorius N. Schedules for Clinical Assessment in NeuropsychiatrySCAN.Arch. Gen. Psychiatry. 1990; 47: 589-593Crossref PubMed Google Scholar SCID, Structured Clinical Interview for DSM disorders;11Spitzer R.L. Williams J.B. Gibbon M. First M.B. The Structured Clinical Interview for DSM-III-R (SCID). I: History, rationale, and description.Arch. Gen. Psychiatry. 1992; 49: 624-629Crossref PubMed Scopus (3284) Google Scholar TGEN1, Translational Genomics Research Institute (genotyping wave 1 with 1190 patients and 401 controls). Open table in a new tab Patients received diagnoses according to the indicated diagnostic criteria and interviews. Protocols and procedures were approved by the local Ethics Committees. Written informed consent was obtained from all patients and controls. Ancestry was assigned to patients and controls on the basis of self-reported ancestry. The samples from Bosnia and Herzegovina / Serbia were merged due to the small number of subjects. The Expanded Reference Group for the WTCCC-BD sample comprised the 1958 British Birth Cohort controls, the UK Blood Services controls supplemented by the other 6 disease sets (coronary artery disease, Crohn's disease, hypertension, rheumatoid arthritis, type 1 and type 2 diabetes) as defined by the WTCCC (2007).1Wellcome Trust Case Control ConsortiumGenome-wide association study of 14,000 cases of seven common diseases and 3,000 shared controls.Nature. 2007; 447: 661-678Crossref PubMed Scopus (7343) Google Scholar The following abbreviations are used: AMDP, Association for Methodology and Documentation in Psychiatry;31The AMDP SystemThe AMDP-System Association of Methodology and Documentation in Psychiatry. Manual For the Assessment and Documentation of Psychopathology. Springer, Berlin1982Google Scholar BD1, bipolar disorder type 1; BD2, bipolar disorder type 2; BD-NOS, bipolar disorder not otherwise specified; CID-I, Composite International Diagnostic Interview;32Peters L. Andrews G. Procedural validity of the computerized version of the Composite International Diagnostic Interview (CIDI-Auto) in the anxiety disorders.Psychol. Med. 1995; 25: 1269-1280Crossref PubMed Scopus (142) Google Scholar, 33Wittchen H.U. Zhao S. Abelson J.M. Abelson J.L. Kessler R.C. Reliability and procedural validity of UM-CIDI DSM-III-R phobic disorders.Psychol. Med. 1996; 26: 1169-1177Crossref PubMed Google Scholar CID-S, Composite International Diagnostic Screener;34Wittchen H.U. Höfler M. Gander F. Pfister H. Storz S. Üstün T.B. Müller N. Kessler R.C. Screening for mental disorders: performance of the Composite International Diagnostic-Screener (CID-S).Int. J. Methods Psychiatr. Res. 1999; 8: 59-70Crossref Scopus (117) Google Scholar DIGS, Diagnostic Interview for Genetic Studies;35Nurnberger Jr., J.I. Blehar M.C. Kaufmann C.A. York-Cooler C. Simpson S.G. Harkavy-Friedman J. Severe J.B. Malaspina D. Reich T. Diagnostic interview for genetic studies. Rationale, unique features, and training.Arch Gen Psychiatry. 1994; 51 (discussion 863–864): 849-859Crossref PubMed Scopus (1722) Google Scholar DSM-III / DSM-IV, Diagnostic and Statistical Manual of Mental Disorders;9American Psychiatric Association (APA)Diagnostic and Statistical Manual of Mental Disorders.Fourth Edition. American Pychiatric Association, Washington, D.C.1994Google Scholar Exp. Ref. Grp., Expanded Reference Group (11,373 controls);1Wellcome Trust Case Control ConsortiumGenome-wide association study of 14,000 cases of seven common diseases and 3,000 shared controls.Nature. 2007; 447: 661-678Crossref PubMed Scopus (7343) Google Scholar FIGS, Family Interview for Genetic Studies;36Maxwell M.E. Family Interview for Genetic Studies (FIGS): Manual For FIGS. Clinical Neurogenetics Branch. Intramural Research Program. National Institute of Mental Health, Bethesda, MD1992Google Scholar GAIN-EA, BD sample with European ancestry from the Genetic Association Information Network (1001 patients and 1033 controls);6Smith E.N. Bloss C.S. Badner J.A. Barrett T. Belmonte P.L. Berrettini W. Byerley W. Coryell W. Craig D. Edenberg H.J. et al.Genome-wide association study of bipolar disorder in European American and African American individuals.Mol. Psychiatry. 2009; 14: 755-763Crossref PubMed Scopus (262) Google Scholar ICD10, International Statistical Classification of Diseases and Related Health Problems;37World Health Organization (WHO)The ICD 10 Classification of Mental and Behavioural Disorders. Clinical Descriptions and Diagnostic Guidelines. WHO, Geneva1992Google Scholar MaD, Manic disorder according to RDC; N, number of subjects; PRIME-MD, Primary Care Evaluation of Mental Disorders;38Spitzer R.L. Williams J.B. Kroenke K. Linzer M. deGruy 3rd, F.V. Hahn S.R. Brody D. Johnson J.G. Utility of a new procedure for diagnosing mental disorders in primary care. The PRIME-MD 1000 study.JAMA. 1994; 272: 1749-1756Crossref PubMed Scopus (2306) Google Scholar RDC, Research Diagnostic Criteria;39Spitzer R.L. Endicott J. Robins E. Research diagnostic criteria: rationale and reliability.Arch. Gen. Psychiatry. 1978; 35: 773-782Crossref PubMed Scopus (5035) Google Scholar SAB, schizoaffective disorder (bipolar type); SADS-L, Schedule for Affective Disorders and Schizophrenia;40Endicott J. Spitzer R.L. A diagnostic interview: the schedule for affective disorders and schizophrenia.Arch. Gen. Psychiatry. 1978; 35: 837-844Crossref PubMed Scopus (4718) Google Scholar SCAN, Schedules for Clinical Assessment in Neuropsychiatry;41Wing J.K. Babor T. Brugha T. Burke J. Cooper J.E. Giel R. Jablenski A. Regier D. Sartorius N. Schedules for Clinical Assessment in NeuropsychiatrySCAN.Arch. Gen. Psychiatry. 1990; 47: 589-593Crossref PubMed Google Scholar SCID, Structured Clinical Interview for DSM disorders;11Spitzer R.L. Williams J.B. Gibbon M. First M.B. The Structured Clinical Interview for DSM-III-R (SCID). I: History, rationale, and description.Arch. Gen. Psychiatry. 1992; 49: 624-629Crossref PubMed Scopus (3284) Google Scholar TGEN1, Translational Genomics Research Institute (genotyping wave 1 with 1190 patients and 401 controls). Lymphocyte DNA was isolated from ethylenediaminetetraacetic acid anticoagulated venous blood by a salting-out procedure using saturated sodium chloride solution16Miller S.A. Dykes D.D. Polesky H.F. A simple salting out procedure for extracting DNA from human nucleated cells.Nucleic Acids Res. 1988; 16: 1215Crossref PubMed Scopus (17178) Google Scholar or by a Chemagic Magnetic Separation Module I (Chemagen, Baesweiler, Germany). Genotyping was performed on HumanHap550v3 BeadArrays (Illumina, San Diego, CA, USA). QC was performed with PLINK17Purcell S. Neale B. Todd-Brown K. Thomas L. Ferreira M.A. Bender D. Maller J. Sklar P. de Bakker P.I. Daly M.J. Sham P.C. PLINK: a tool set for whole-genome association and population-based linkage analyses.Am. J. Hum. Genet. 2007; 81: 559-575Abstract Full Text Full Text PDF PubMed Scopus (16836) Google Scholar (version 1.05). In detail, the X-chromosomal heterozygosity rates were used to determine the sex of each subject; subjects with a discrepant sex status were excluded (five patients and three controls). Subjects with a call rate (CR) < 0.97 were also excluded (eight patients and 26 controls). Using identical-by-state (IBS) analysis, cryptically related individuals (IBS > 1.65) were identified, and the DNA sample with the lower CR was removed. For the identification of possible population stratification, a multidimensional scaling (MDS) analysis was performed. In total, seven patients and 32 controls were excluded on the basis of relatedness or outlier detection. SNPs with a CR < 0.98 and monomorphic SNPs were excluded (18,618 SNPs in patients and 14,880 in controls). Additional markers were excluded on the basis of nonrandom differences in missingness patterns with respect to phenotype and for significant results in the “pseudo” patient-control analysis using control samples and a Cochran-Armitage test for linear trend (TREND) (a total of 7101 SNPs in patients and 8076 in controls). SNPs with a minor allele frequency (MAF) < 1% in patients or controls were excluded (11,434 in patients and 12,155 in controls), as were SNPs in Hardy-Weinberg disequilibrium (Hardy-Weinberg equilibrium [HWE], pexact < 1 × 10−4, 351 SNPs in controls; pexact < 1 × 10−6, 132 SNPs in patients). With the use of the remaining patients and controls, a MDS analysis was performed, first with patients and controls from our GWAS sample and then with the GWAS sample and unrelated individuals from the CEU (Utah residents with ancestry from northern and western Europe), CHB (Han Chinese in Beijing, China), JPT (Japanese in Tokyo, Japan), and YRI (Yoruba in Ibadan, Nigeria) HapMap panels. On the basis of this analysis, seven controls and zero patients were excluded (Figure S2). At the marker level, nonrandom missingness patterns were identified with the use of PLINK's “mishap” test, and another 1825 SNPs were excluded. In total, we excluded 20 patients and 68 controls as well as 49,488 SNPs in the course o