IDENTIFYING DRUG TARGETS FOR SCHIZOPHRENIA THROUGH GENE PRIORITIZATION

Abstract

The latest schizophrenia GWAS meta-analysis found 287 loci that reached genome-wide statistical significance (67,390 cases and 94,015 controls). In these loci, 120 genes were prioritized using fine-mapping, summary-based Mendelian Randomization (SMR), and enhancer-promoter interaction (via Hi-C). However, these methods only use information within a given locus, ignoring information from the rest of the genome. Combining locus-based approaches with tools that incorporate genome-wide information such as the Polygenic Priority Score (PoPS) have been shown to improve gene prioritization precision. To more accurately characterize genes that play a role in schizophrenia etiology, we prioritized 62 genes based on their distance to GWAS signals, PoPS, fine-mapped coding variants, and ultra-rare coding variant burden tests. We prioritized DRD2, the target of most approved antipsychotics, which was not highlighted by previous efforts. In addition, we prioritized 9 genes that are targeted by approved or investigational drugs and may therefore present drug repurposing opportunities. These included drugs targeting calcium channels (CACNA1C and CACNB2), glutamatergic receptors (GRIN2A and GRM3), and GABAB receptor (GABBR2). We highlighted 3 additional genes (PDE4B, VRK2, and PLCL2) in loci that are shared with a recent addiction GWAS. While it is challenging to assess psychotic symptoms in rodents, high-quality rodent addiction models exist for a wide range of substances. Modulation of these genes could be tested in rodent addiction models and, if successful, may warrant further testing in human clinical trials of addiction and/or schizophrenia. Adding to previous gene prioritization efforts, we hope that our list of prioritized genes will ultimately facilitate the development of new medicines for people living with schizophrenia.