disc1 mrna expression is not influenced by common cisacting regulatory polymorphisms or imprinting the hypothesis that genetic variation in disrupted in schizophrenia 1 disc1 influences risk of schizophrenia and other major psychiatric disorders is supported by a growing body of genetic association data and plausible functional biology risk of psychiatric disorder is not attributable to nonsynonymous changes that alter the protein coding sequence of disc1 although certain such variants possibly contribute to risk haplotypes thus it is widely hypothesized that the risk variants at disc1 influence its expression as a complicating factor it has also been recently proposed that disc1 is subject to imprinting a hypothesis that would profoundly influence the interpretation of current genetic studies we have tested these two main hypotheses using allelic expression analysis of 148 human brain mrna samples 65 were informative for analysis however only a single sample showed evidence for unequal expression of paternal and maternal transcripts analysis of the proximal promoter region in that subject revealed the presence of a previously unknown duplication of the 22 nucleotides 168 to 147 relative to the transcription start site however the altered expression in that subject did not appear to be explained by this insertion our data robustly demonstrate that disc1 is not imprinted in the adult human brain and strongly suggest that reports of genetic association between disc1 and psychiatric disorder are not explicable by sequence changes that alter mrna abundance