Meta-analysis of Genome-wide Association Studies for Neuroticism, and the Polygenic Association With Major Depressive Disorder
Authors: Marleen H. M. de Moor, Stéphanie M. van den Berg, Karin J. H. Verweij, Robert F. Krueger, Michelle Luciano, Alejandro Arias Vasquez, Lindsay K. Matteson, Jaime Derringer, Tõnu Esko, Najaf Amin, Scott D. Gordon, Narelle K. Hansell, Amy B. Hart, Ilkka Seppälä, Jennifer E. Huffman, Bettina Konte, Jari Lahti, Minyoung Lee, Mike Miller, Teresa Nutile, Toshiko Tanaka, Alexander Teumer, Alexander Viktorin, Juho Wedenoja, Goncalo R. Abecasis, Daniel E. Adkins, Arpana Agrawal, Jüri Allik, Katja Appel, Timothy B. Bigdeli, Fabio Busonero, Harry Campbell, Paul T. Costa, George Davey Smith, Gail Davies, Harriet de Wit, Jun Ding, Barbara E. Engelhardt, Johan G. Eriksson, Iryna O. Fedko, Luigi Ferrucci, Barbara Franke, Ina Giegling, Richard Grucza, Annette M. Hartmann, Andrew C. Heath, Kati Heinonen, Anjali K. Henders, Georg Homuth, Jouke-Jan Hottenga, William G. Iacono, Joost Janzing, Markus Jokela, Robert Karlsson, John P. Kemp, Matthew G. Kirkpatrick, Antti Latvala, Terho Lehtimäki, David C. Liewald, Pamela A. F. Madden, Chiara Magri, Patrik K. E. Magnusson, Jonathan Marten, Andrea Maschio, Sarah E. Medland, Evelin Mihailov, Yuri Milaneschi, Grant W. Montgomery, Matthias Nauck, Klaasjan G. Ouwens, Aarno Palotie, Erik Pettersson, Ozren Polasek, Yong Qian, Laura Pulkki-Råback, Olli T. Raitakari, Anu Realo, Richard J. Rose, Daniela Ruggiero, Carsten O. Schmidt, Wendy S. Slutske, Rossella Sorice, John M. Starr, Beate St Pourcain, Angelina R. Sutin, Nicholas J. Timpson, Holly Trochet, Sita Vermeulen, Eero Vuoksimaa, Elisabeth Widen, Jasper Wouda, Margaret J. Wright, Lina Zgaga, David Porteous, Alessandra Minelli, Abraham A. Palmer, Dan Rujescu, Marina Ciullo, Caroline Hayward, Igor Rudan, Andres Metspalu, Jaakko Kaprio, Ian J. Deary, Katri Räikkönen, James F. Wilson, Liisa Keltikangas-Järvinen, Laura J. Bierut, John M. Hettema, Hans J. Grabe, Cornelia M. van Duijn, David M. Evans, David Schlessinger, Nancy L. Pedersen, Antonio Terracciano, Matt McGue, Brenda W. J. H. Penninx, Nicholas G. Martin, Dorret I. Boomsma
Journal: JAMA Psychiatry (2015)

<h3>Importance</h3> Neuroticism is a pervasive risk factor for psychiatric conditions. It genetically overlaps with major depressive disorder (MDD) and is therefore an important phenotype for psychiatric genetics. The Genetics of Personality Consortium has created a resource for genome-wide association analyses of personality traits in more than 63 000 participants (including MDD cases). <h3>Objectives</h3> To identify genetic variants associated with neuroticism by performing a meta-analysis of genome-wide association results based on 1000 Genomes imputation; to evaluate whether common genetic variants as assessed by single-nucleotide polymorphisms (SNPs) explain variation in neuroticism by estimating SNP-based heritability; and to examine whether SNPs that predict neuroticism also predict MDD. <h3>Design, Setting, and Participants</h3> Genome-wide association meta-analysis of 30 cohorts with genome-wide genotype, personality, and MDD data from the Genetics of Personality Consortium. The study included 63 661 participants from 29 discovery cohorts and 9786 participants from a replication cohort. Participants came from Europe, the United States, or Australia. Analyses were conducted between 2012 and 2014. <h3>Main Outcomes and Measures</h3> Neuroticism scores harmonized across all 29 discovery cohorts by item response theory analysis, and clinical MDD case-control status in 2 of the cohorts. <h3>Results</h3> A genome-wide significant SNP was found on 3p14 in<i>MAGI1</i>(rs35855737;<i>P</i> = 9.26 × 10<sup>−9</sup>in the discovery meta-analysis). This association was not replicated (<i>P</i> = .32), but the SNP was still genome-wide significant in the meta-analysis of all 30 cohorts (<i>P</i> = 2.38 × 10<sup>−8</sup>). Common genetic variants explain 15% of the variance in neuroticism. Polygenic scores based on the meta-analysis of neuroticism in 27 cohorts significantly predicted neuroticism (1.09 × 10<sup>−12</sup> &lt; <i>P</i> &lt; .05) and MDD (4.02 × 10<sup>−9</sup> &lt; <i>P</i> &lt; .05) in the 2 other cohorts. <h3>Conclusions and Relevance</h3> This study identifies a novel locus for neuroticism. The variant is located in a known gene that has been associated with bipolar disorder and schizophrenia in previous studies. In addition, the study shows that neuroticism is influenced by many genetic variants of small effect that are either common or tagged by common variants. These genetic variants also influence MDD. Future studies should confirm the role of the<i>MAGI1</i>locus for neuroticism and further investigate the association of<i>MAGI1</i>and the polygenic association to a range of other psychiatric disorders that are phenotypically correlated with neuroticism.