Authors: Michael Zech, Ivana Dzinovic, Matej Skorvanek, Philip Harrer, Jan Necpal, Robert Kopajtich, Volker Kittke, Erik Tilch, Chen Zhao, Eugenia Tsoma, Ugo Sorrentino, Elisabetta Indelicato, Antonia Stehr, Alice Saparov, Lucia Abela, Miriam Adamovicova, Alexandra Afenjar, Birgit Assmann, Janette Baloghova, Matthias Baumann, Riccardo Berutti, Zuzana Brezna, Melanie Brugger, Theresa Brunet, Benjamin Cogne, Isabel Colangelo, Erin Conboy, Felix Distelmaier, Matthias Eckenweiler, Barbara Garavaglia, Arie Geerlof, Elisabeth Graf, Annette Hackenberg, Denisa Harvanova, Bernhard Haslinger, Petra Havrankova, Georg F Hoffmann, Wibke G Janzarik, Boris Keren, Miriam Kolnikova, Konstantinos Kolokotronis, Zuzana Kosutzka, Anne Koy, Martin Krenn, Magdalena Krygier, Katarina Kusikova, Oliver Maier, Thomas Meitinger, Christian Mertes, Ivan Milenkovic, Edoardo Monfrini, Andre Santos Dias Mourao, Thomas Musacchio, Mathilde Nizon, Miriam Ostrozovicova, Martin Pavlov, Iva Prihodova, Irena Rektorova, Luigi M Romito, Barbora Rybanska, Ariane Sadr-Nabavi, Susanne Schwenger, Ali Shoeibi, Alexandra Sitzberger, Dmitrii Smirnov, Jana Svantnerova, Raushana Tautanova, Sandra P Toelle, Olga Ulmanova, Francesco Vetrini, Katharina Vill, Matias Wagner, David Weise, Giovanna Zorzi, Alessio Di Fonzo, Konrad Oexle, Steffen Berweck, Volker Mall, Sylvia Boesch, Barbara Schormair, Holger Prokisch, Robert Jech, Juliane Winkelmann.

Whole-genome sequencing (WGS) offers the advantage of detecting all potential disease-relevant variations, but its widespread use requires evidence of diagnostic effectiveness for specific conditions. Although exome sequencing (ES) has facilitated gene discovery in dystonia, its diagnostic yield remains limited, typically capped at around 50%. WGS as a second-tier test in dystonia cases with uninformative ES remained unclear. This study illustrates that the transition from ES to WGS in long-standing undiagnosed patients increases diagnostic capabilities.

Between 2015 and 2024, a multinational research network recruited patients with unexplained dystonia for genomic investigation, excluding those with known monogenic or secondary causes. Standardized phenotyping and clinical data were collected to support variant interpretation. The ES was performed on all participants, followed by WGS in unresolved cases. Complementary assays – including RNA-seq, quantitative proteomics, immunoblotting, and enzyme activity tests – were used to validate findings and explore candidate genes. A large proteomics dataset enabled outlier detection, while functional studies, such as analysis of PRMT1 variants, supported the pathogenicity of novel mutations.

In a large, multinational study, 2,874 individuals from 1,825 families with dystonia were enrolled for ES, with a subset undergoing WGS and multi-omic analyses. ES diagnosed 21.7% of index patients, with higher yields in studies including relatives and underrepresented populations. WGS further diagnosed 12.1% of cases, uncovering variants missed by ES.  The study highlighted the genetic heterogeneity of dystonia and revealed expanded roles for neurodevelopmental genes like ANK2 and CHD3 in dystonia pathogenesis. Candidate gene analysis using WGS identified PRMT1 as a novel contributor to neurodevelopmental dystonia through de-novo missense variants that impair protein stability or enzymatic function, supporting a loss-of-function mechanism.

This decade-long study demonstrates that combining ES and WGS with proteomics and other multi-omic approaches significantly improves diagnostic yield, particularly in complex or long-unsolved cases. WGS identified additional pathogenic variants missed by ES, while proteomics validated uncertain findings and revealed undetected expression defects. The study uncovered novel genetic contributors like PRMT1 and emphasized the underrecognized role of repeat-expansion variants in dystonia. Although limitations remain, this work shows that integrated multi-omic strategies can end prolonged diagnostic journeys, guide treatment decisions, and may qualify patients for emerging gene-targeted therapies.