Supplementary Material for: <i>DTNBP1, NRG1, DAOA</i>, <i>DAO</i> and <i>GRM3</i> Polymorphisms and Schizophrenia: An Association Study

<i>Background:</i> Several studies of the dystrobrevin-binding protein 1 gene <i>(DTNBP1)</i>, neuregulin 1 <i>(NRG1)</i>, <i>D</i>-amino-acid oxidase <i>(DAO)</i>, <i>DAO</i> activator <i>(DAOA, G72)</i>, and metabotropic glutamate receptor 3 <i>(GRM3)</i> genes have suggested an association between variants of these genes and schizophrenia. <i>Methods:</i> In a replication attempt, single-nucleotide polymorphisms of the <i>DTNBP1, NRG1, DAO, DAOA, </i>and<i> GRM3 </i>genes were analyzed in three independent Scandinavian schizophrenia case-control samples. <i>Results:</i> One <i>DTNBP1 </i>and three <i>GRM3</i> single-nucleotide polymorphisms showed nominal significant associations to the disease. However, after correction for multiple testing, there were no statistically significant allele, genotype or haplotype case-control differences. <i>Conclusions:</i> The present Scandinavian results do not verify previous associations between the analyzed <i>DTNBP1, NRG1, DAO, DAOA, </i>and<i> GRM3 </i>gene polymorphisms and schizophrenia. Additional studies and meta-analyses are warranted to shed further light on these relationships.