of the known schizophrenia variants showed a robust association with any of the endophenotypes. One suggestive single-variant result was for an intronic variant in the gene contactin 4 (CNTN4) associated with both antisaccade and P300, although this association did not survive multiple testing correction for all phenotypes. CNTN4 is a member of the contactin family of immunoglobulins that functions in neuronal network formation and plasticity. Deletion or mutation in CNTN4 has been found to be associated with autism spectrum disorders (Fernandez et al. 2004), and, of course, schizophrenia (Schizophrenia Working Group of the Psychiatric Genomics Consortium, 2014). The other variant was in an intron of the gene for prostaglandin-I synthase (PTGIS) which encodes for proteins in the cytochrome P450 enzyme superfamily.
