With the recent revolutionizing introduction of Next Generation Sequencing (NGS) as diagnostic tool in the field of medical genetics, screening genomic DNA to try to uncover the underlying mutations responsible for genetic disorders became fast, straightforward and cheap. Although the disease-causing nature of mutations identified in patient DNA sequence is obvious in most cases, in up to 20% of the cases the causality of the variant identified is doubtful (variants of unknown significance (VUS)). Patients carrying a VUS remain uncertain about their diagnosis. Therefore, nowadays the major challenge in genetic diagnostics is not the sequencing itself anymore, but the bottle-neck is rather the characterization of those ""unclear"" variants.
In this project we aim to use our in-house developed CRISPR/Cas-mediated genome editing platform to introduce VUS into model organisms in order to assess their disease-causing nature in a complex biological system. For this purpose we use the zebrafish as a relevant and widely used vertebrate disease model. We specifically focus on the modelling of heritable connective tissue disorders including bone and cardiovascular diseases, since over the last couple of years we established, phenotyped and molecularly studied several zebrafish models for these disorders. In case the VUS is indeed responsible for the disease, the zebrafish model will reveal a disease phenotype whereas a wild-type phenotype will be observed when the variant is not disease causing.
Our strategy has valorization potential towards tests for molecular diagnosis and patient management in general and more specifically for prenatal diagnosis, preimplantation genetic diagnosis and patient stratification for risk estimation and personalized healthcare. The successful development of a new in vivo bioassay to model the effects of VUS will be an interesting tool to add to the portfolio of direct-to-consumer and clinical genetic testing companies around the world. On the other hand, in the case it can be shown that the costs of these bioassays outweigh the burden on health insurance costs as well as on the patient's quality of life resulting from inconclusive or incorrect interpretation of genetic test results, it can be expected that these tests will become reimbursable by health insurance, potentially leading to a wide-spread usage of our bioassay by clinical geneticists.