In CARDIOREPAIR, we aim to identify and repair disease-causing variants in dilated cardiomyopathy (DCM), the major contributor to heart failure. We focus on the gene RBM20 mutated in patients with a highly penetrant and aggressive form of familial DCM. We will create a comprehensive map of all possible RBM20 variants that can cause DCM and develop a therapeutic approach for mutations with the strongest effect size. Enabled by a multitude of new technologies developed in our groups, the primary goal is to characterize the complete spectrum of amino acid mutations in RBM20 by high-throughput saturation mutagenesis screens. Combined with functional readouts and multi-omics analysis of downstream processes, we will classify and score the pathogenicity of each individual mutant (objective 1). To this end, we will cover both the known DCM-causing RBM20 variants, as well as those that have not been identified in patients yet. Each mutant, represented by a typical transcriptomic, proteomic, phosphoproteomic, and microscopic fingerprint, will guide us in finding novel class-specific therapeutic strategies to revert the deviant phenotype back to the healthy state. For a subset of mutants representing each identified mutation class, we will generate mouse models and investigate changes in heart physiology and ultrastructure linked to the altered ‘ome’ profile. Our second goal is to establish a class-specific therapeutic approach for the treatment of patients harboring RBM20 mutations (objective 2). We will implement our advances in muscle-specific gene editing, focusing on prime editing and nanobody-guided approaches to specifically tackle the mutations leading to RBM20 translocation. This proposal serves as a blueprint for going from variant identification to therapy in an accelerated fashion by harnessing and combining the power of high-throughput functional genomics and bioengineering and therefore is widely applicable to other cardiovascular diseases (CVD).