Field synopsis and systematic meta-analyses of genetic association studies in isolated dystonia

Background and objectives: Dystonia is a genetically complex disease with both monogenic and polygenic causes. For the latter, numerous genetic associations studies have been performed with largely inconsistent results. The aim of this study was to perform a field synopsis including systematic meta-analyses of genetic association studies in isolated dystonia. Methods: For the field synopsis we systematically screened and scrutinized the published literature using NCBI's PubMed database. For genetic variants with sufficient information in at least two independent datasets, random-effects meta-analyses were performed, including meta-analyses stratified by ethnic descent and dystonia subtypes. Results: A total of 3575 articles were identified and scrutinized resulting in the inclusion of 42 independent publications allowing 134 meta-analyses on 45 variants across 17 genes. While our meta-analyses pinpointed several association signals with variants in TOR1A, DRD1, and ARSG, no single variant displayed compelling association with dystonia in the available data. Conclusions: Our study provides an up-to-date summary of the status of dystonia genetic association studies. Additional large-scale studies are needed to better understand the genetic causes of isolated dystonia.