title: Gender differences in CNV burden do not confound schizophrenia CNV associations.
abstract: Compared with the general population, an excess of rare copy number variants (CNVs) has been identified in people with schizophrenia. Females with neurodevelopmental disorders and in the general population have been reported to carry more large, rare CNVs than males. Given that many schizophrenia datasets do not have equal gender ratios in cases and controls, sex differences in CNV burden might have impacted on estimates of case-related CNV burden and also on associations to individual loci. In a sample of 13,276 cases and 17,863 controls, we observed a small but significant excess of large (≥500 Kb), rare (<1%) CNVs in females compared with males in both cases and controls (OR = 1.17, P = 0.0012 for controls; OR = 1.11, P = 0.045 for cases). The burden of 11 schizophrenia-associated CNVs was significantly higher in female cases compared with male cases (OR = 1.38, P = 0.0055), but after accounting for the rates of CNVs in controls, we found no significant gender difference in the risk conferred by these loci. Controlling for gender had a negligible effect on the significance of association between specific CNVs and schizophrenia. The female excess of large CNVs in both cases and controls suggests a female protective mechanism exists for deleterious CNVs that may extend beyond neurodevelopmental phenotypes.
authors.affiliation: Medical Research Council Centre for Neuropsychiatric Genetics and Genomics, Cardiff University, Cardiff, Wales, UK.
authors.forename: Jun
authors.initials: J
authors.lastname: Han
authors.affiliation: Medical Research Council Centre for Neuropsychiatric Genetics and Genomics, Cardiff University, Cardiff, Wales, UK.
authors.forename: James T R
authors.initials: JT
authors.lastname: Walters
authors.affiliation: Medical Research Council Centre for Neuropsychiatric Genetics and Genomics, Cardiff University, Cardiff, Wales, UK.
authors.forename: George
authors.initials: G
authors.lastname: Kirov
authors.affiliation: Medical Research Council Centre for Neuropsychiatric Genetics and Genomics, Cardiff University, Cardiff, Wales, UK.
authors.forename: Andrew
authors.initials: A
authors.lastname: Pocklington
authors.affiliation: Medical Research Council Centre for Neuropsychiatric Genetics and Genomics, Cardiff University, Cardiff, Wales, UK.
authors.forename: Valentina
authors.initials: V
authors.lastname: Escott-Price
authors.affiliation: Medical Research Council Centre for Neuropsychiatric Genetics and Genomics, Cardiff University, Cardiff, Wales, UK.|Division of Psychological Medicine and Clinical Neurosciences, Cardiff University, Cardiff, Wales, UK.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Owen
authors.affiliation: Medical Research Council Centre for Neuropsychiatric Genetics and Genomics, Cardiff University, Cardiff, Wales, UK.
authors.forename: Peter
authors.initials: P
authors.lastname: Holmans
authors.affiliation: Medical Research Council Centre for Neuropsychiatric Genetics and Genomics, Cardiff University, Cardiff, Wales, UK.
authors.forename: Michael C
authors.initials: MC
authors.lastname: O'Donovan
authors.affiliation: Medical Research Council Centre for Neuropsychiatric Genetics and Genomics, Cardiff University, Cardiff, Wales, UK.
authors.forename: Elliott
authors.initials: E
authors.lastname: Rees
mesh_terms: D016022:Case-Control Studies; D056915:DNA Copy Number Variations; D005260:Female; D020022:Genetic Predisposition to Disease; D055106:Genome-Wide Association Study; D006801:Humans; D008297:Male; D012559:Schizophrenia / Q000235:genetics*; D012727:Sex Characteristics