title: Resequencing and association analysis of coding regions at twenty candidate genes suggest a role for rare risk variation at AKAP9 and protective variation at NRXN1 in schizophrenia susceptibility.
abstract: A fraction of genetic risk to develop schizophrenia may be due to low-frequency variants. This multistep study attempted to find low-frequency variants of high effect at coding regions of eleven schizophrenia susceptibility genes supported by genome-wide association studies (GWAS) and nine genes for the DISC1 interactome, a susceptibility gene-set. During the discovery step, a total of 125 kb per sample were resequenced in 153 schizophrenia patients and 153 controls from Galicia (NW Spain), and the cumulative role of low-frequency variants at a gene or at the DISC1 gene-set were analyzed by burden and variance-based tests. Relevant results were meta-analyzed when appropriate data were available. In addition, case-only putative damaging variants were genotyped in a further 419 cases and 398 controls. The discovery step revealed a protective effect of rare missense variants at NRXN1, a result supported by meta-analysis (OR = 0.67, 95% CI: 0.47-0.94, P = 0.021, based on 3848 patients and 3896 controls from six studies). The follow-up step based on case-only putative damaging variants revealed a promising risk variant at AKAP9. This variant, K873R, reached nominal significance after inclusion of 240 additional Spanish controls from databases. The variant, located in an ADCY2 binding region, is absent from large public databases. Interestingly, GWAS revealed an association between common ADCY2 variants and bipolar disorder, a disorder with considerable genetic overlap with schizophrenia. These data suggest a role of rare missense variants at NRXN1 and AKAP9 in schizophrenia susceptibility, probably related to alteration of the excitatory/inhibitory synaptic balance, deserving further investigation.
authors.affiliation: Instituto de Investigación Sanitaria (IDIS) de Santiago de Compostela, Complexo Hospitalario Universitario de Santiago (CHUS), Servizo Galego de Saúde (SERGAS), Santiago de Compostela, Spain; Grupo de Medicina Xenómica, Universidade de Santiago de Compostela, Santiago de Compostela, Spain.
authors.forename: José Javier
authors.initials: JJ
authors.lastname: Suárez-Rama
authors.affiliation: Instituto de Investigación Sanitaria (IDIS) de Santiago de Compostela, Complexo Hospitalario Universitario de Santiago (CHUS), Servizo Galego de Saúde (SERGAS), Santiago de Compostela, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Arrojo
authors.affiliation: Instituto de Investigación Sanitaria (IDIS) de Santiago de Compostela, Complexo Hospitalario Universitario de Santiago (CHUS), Servizo Galego de Saúde (SERGAS), Santiago de Compostela, Spain; Fundación Pública Galega de Medicina Xenómica, Complexo Hospitalario Universitario de Santiago (CHUS), Servizo Galego de Saúde (SERGAS), Santiago de Compostela, Spain.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Sobrino
authors.affiliation: Instituto de Investigación Sanitaria (IDIS) de Santiago de Compostela, Complexo Hospitalario Universitario de Santiago (CHUS), Servizo Galego de Saúde (SERGAS), Santiago de Compostela, Spain; Grupo de Medicina Xenómica, Universidade de Santiago de Compostela, Santiago de Compostela, Spain.
authors.forename: Jorge
authors.initials: J
authors.lastname: Amigo
authors.affiliation: Instituto de Investigación Sanitaria (IDIS) de Santiago de Compostela, Complexo Hospitalario Universitario de Santiago (CHUS), Servizo Galego de Saúde (SERGAS), Santiago de Compostela, Spain; Servizo de Psiquiatría, Complexo Hospitalario Universitario de Santiago(CHUS), Servizo Galego de Saúde (SERGAS), Santiago de Compostela, Spain.
authors.forename: Julio
authors.initials: J
authors.lastname: Brenlla
authors.affiliation: Instituto de Investigación Sanitaria (IDIS) de Santiago de Compostela, Complexo Hospitalario Universitario de Santiago (CHUS), Servizo Galego de Saúde (SERGAS), Santiago de Compostela, Spain; Servizo de Psiquiatría, Complexo Hospitalario Universitario de Santiago(CHUS), Servizo Galego de Saúde (SERGAS), Santiago de Compostela, Spain.
authors.forename: Santiago
authors.initials: S
authors.lastname: Agra
authors.affiliation: Instituto de Investigación Sanitaria (IDIS) de Santiago de Compostela, Complexo Hospitalario Universitario de Santiago (CHUS), Servizo Galego de Saúde (SERGAS), Santiago de Compostela, Spain; Servizo de Psiquiatría, Complexo Hospitalario Universitario de Santiago(CHUS), Servizo Galego de Saúde (SERGAS), Santiago de Compostela, Spain.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Paz
authors.affiliation: Instituto de Investigación Sanitaria (IDIS) de Santiago de Compostela, Complexo Hospitalario Universitario de Santiago (CHUS), Servizo Galego de Saúde (SERGAS), Santiago de Compostela, Spain.
authors.forename: María
authors.initials: M
authors.lastname: Brión
authors.affiliation: Instituto de Investigación Sanitaria (IDIS) de Santiago de Compostela, Complexo Hospitalario Universitario de Santiago (CHUS), Servizo Galego de Saúde (SERGAS), Santiago de Compostela, Spain; Grupo de Medicina Xenómica, Universidade de Santiago de Compostela, Santiago de Compostela, Spain; Fundación Pública Galega de Medicina Xenómica, Complexo Hospitalario Universitario de Santiago (CHUS), Servizo Galego de Saúde (SERGAS), Santiago de Compostela, Spain.
authors.forename: Ángel
authors.initials: Á
authors.lastname: Carracedo
authors.affiliation: Instituto de Investigación Sanitaria (IDIS) de Santiago de Compostela, Complexo Hospitalario Universitario de Santiago (CHUS), Servizo Galego de Saúde (SERGAS), Santiago de Compostela, Spain; Servizo de Psiquiatría, Complexo Hospitalario Universitario de Santiago(CHUS), Servizo Galego de Saúde (SERGAS), Santiago de Compostela, Spain.
authors.forename: Mario
authors.initials: M
authors.lastname: Páramo
authors.affiliation: Instituto de Investigación Sanitaria (IDIS) de Santiago de Compostela, Complexo Hospitalario Universitario de Santiago (CHUS), Servizo Galego de Saúde (SERGAS), Santiago de Compostela, Spain. Electronic address: javier.costas.costas@sergas.es.
authors.forename: Javier
authors.initials: J
authors.lastname: Costas
mesh_terms: D054758:A Kinase Anchor Proteins / Q000235:genetics*; D000262:Adenylyl Cyclases / Q000235:genetics; D002135:Calcium-Binding Proteins; D015816:Cell Adhesion Molecules, Neuronal / Q000235:genetics*; D003598:Cytoskeletal Proteins / Q000235:genetics*; D030541:Databases, Genetic; D005260:Female; D020022:Genetic Predisposition to Disease; D055106:Genome-Wide Association Study; D006801:Humans; D008297:Male; D009419:Nerve Tissue Proteins / Q000235:genetics*; D019006:Neural Cell Adhesion Molecules; D016366:Open Reading Frames; D020641:Polymorphism, Single Nucleotide; D012306:Risk; D012559:Schizophrenia / Q000235:genetics*; D013030:Spain
chemical_list: D054758:A Kinase Anchor Proteins; C119719:AKAP9 protein, human; D002135:Calcium-Binding Proteins; D015816:Cell Adhesion Molecules, Neuronal; D003598:Cytoskeletal Proteins; C412476:DISC1 protein, human; C539628:NRXN1 protein, human; D009419:Nerve Tissue Proteins; D019006:Neural Cell Adhesion Molecules; D000262:Adenylyl Cyclases; C100622:adenylyl cyclase 2
keywords: AKAP9; DISC1; NRXN1; Psychosis; SNV; Single nucleotide variant