We reported results for association tests between psychophysiological endophenotypes and SNPs discovered through whole genome sequencing. Association results identified no genome-wide significant variants, after accounting for the many millions of tests conducted here. Gene-based burden tests identified four potential signals, in ANXA3, GBX2, KIF18A, and SLC27A6 genes, associated with antisaccade error, EEG beta power, pleasant difference startle modulation, and aversive difference startle modulation, respectively. ANXA3 is part of a signal transduction pathway and the regulation of cell growth, and has not been associated previously with endophenotypes or phenotypes relevant to antisaccade performance. GBX2, gastrulation brain homeobox 2, is involved in brain development in the mid/hindbrain region, and controls the proper expression of other genes during embryogenesis. The GBX2 association was marginally significant, based on only two relatively poorly imputed singletons, and should be interpreted with additional skepticism until replication. SLC27A6 is a solute carrier not expressed in the brain and KIF18A is involved in chromosome congression during mitosis and meiosis, limiting interpretative speculation about their roles in modulated startle.
