ANK3 gene variants have consistently been associated withbipolar spectrum disorder and schizophrenia spectrum disorder. However, therelevance of its encoded protein, ankyrin-3, in these disorders remainselusive. Here, we show that ANK3 gene expression in bloodis significantly increased in bipolar disorder and schizophrenia comparedwith healthy controls. Additionally, we identified potential cis-actingexpression quantitative trait loci located close to the transcription startsite of one of the isoforms of the gene. These findings suggest that ANK3 mRNA is an interesting marker for furtherinvestigation of the underlying mechanisms in psychotic disorders.