["Several case-control studies examined an association between schizophrenia and the 40-bp variable number tandem repeat (VTNR) polymorphism in the 3'-UTR of the dopamine transporter gene (SLC6A3). The results of these studies have been equivocal due to small sample size and low power. This meta-analysis has the aim to evaluate the collective evidence for an association between the VTNR polymorphism and schizophrenia.", 'Different meta-analyses were performed, sequentially considering the 9- and 10-repeat alleles and different genotypes (genotypes 9/9, 9/10, 10/10) as risk factors for schizophrenia. Analyses of the alleles included 659 cases and 563 controls from six case-control studies.', 'The pooled OR from each analysis approximated 1.0, and none were significant. Lack of significance attributable to the negative effects of single large studies or to heterogeneity between the studies was excluded.'] Does meta-analysis show schizophrenia is not associated with the 40-base-pair repeat polymorphism of the dopamine transporter gene?