Diagnostic Research in Patients With Rare Diseases -Solving the Unsolved Rare Diseases

Most diagnostically unsolved rare disease have a genetic cause. These causes have not been found applying the current methodologies due to technical limitations (e.g. repeat expansions, changes in non-coding (intronic) regions) or, although methodically recorded, their pathophysiological significance but not classified as clinically relevant. A re- and meta-analysis of existing data sets with new algorithms and statistical models as well as the complementation with other omics technologies followed by functional follow-up studies in appropriate disease models (e.g. patient cell lines) allows to elucidate additional causes of diseases and improve the diagnosis of hereditary diseases. In addition to the direct examination of persons affected, the analysis of healthy family members, for example of parents, plays an important role in a so-called trio analysis, especially in the efficient filtering of the extensive data sets for newly created changes, so-called de novo- Variants (new mutations). In the context of the outlined analyzes, new disease genes can be found and validated. The gain of scientific knowledge due to a better understanding of basic cell biological mechanisms can contribute to the development of targeted therapeutic approaches. In this context, the Solve-RD project has been built and financed by the European Union with the ambitions to solve large numbers of rare disease, for which a molecular cause is not known yet by sophisticated combined omics approaches, and to improve diagnostics of rare disease patients. Solve-RD fully integrates with the newly formed European Reference Networks (ERNs) for rare diseases, and in particular the ERN-RND, -EURO-NMD, -ITHACA, and -GENTURIS. The AnDDI-Rares network is fully affiliated to the ERN ITHACA network and will actively contribute to the project, by the ambition of sharing knowledge about genes, genomic variants and phenotypes. The project will first reanalyse 18.000 negative exomes from the different ERNs performed in a diagnostic or research context (collection of biomaterial, clinical/phenotypic data plus next-generation sequencing has already been performed, and the patient/family has agreed previously in writing that their sample could be used for research related to their disease, with no study related presence required. The project will also propose new multi-omics analyses with new samples needed in 500 patients and their parents in total, justifying the AnDDI-Solve-RD project.