A first episode psychosis case-control genetic association study

Background:GAP(genesandpsychosis) is a case-control studyof first episode psychosis conducted in London and Cambridge, which aims to identify genes conferring susceptibility to psychosis, and associated phenotypes including cognitive dysfunction and cerebral morphology. Methods:First episode psychosis cases have been recruited in South London and Maudsley NHS Trust and in Cambridge. A variety of demographic and clinical data have been collected. In a subset of these, neurocognitive assessments and MRIs have been performed. Samples have been taken for DNA, and in a subset for RNA and proteomic analysis. Genetic association analysis is being undertaken using a candidate gene approach. The genes chosen for the first wave of analysis include the current most promising candidates for suscept-ibility to psychosis (NRG1, dysbindin, DISC1, G72, etc) as well as candidates for susceptibility to cannabis misuse (COMT), cognitive dysfunction, dysregulation of brain morphology or susceptibility to bipolar disorder (e.g. LIS1), and candidates in the dopamine and serotonin neurotransmitter systems. Results:DNA has been collected from 302 patients to date. Of these, 72%aremale, and themeanage is 25 years; 187 areCaucasian; 115 are of black origin; and the rest are of other ormixed ethnicity. Genotyping is being undertaken in this sample and in matched controls. Conclusions:Data is being reported separately for a number of phenotypes forwhich there is already somedata. This presentationwill report the overall genetic association results.