Tatiana Maroilley, Univeristy of Calgary, Canada

The Silent Genomes (SG) Project aims to reduce diagnosis access barriers for Indigenous children with genetic rare diseases (RDs). This project was built and is led in collaboration with First Nations, Inuit, and Métis partners to ensure cultural safety, establish processes for Indigenous governance of biological samples and genome data, and build tools and Indigenous human capacity to establish long-term equitable access to genomics-guided care. Researchers involved in the SG Project regularly meet with Indigenous organizations, patients, and committees to present developments in the conducted research. Communications and academic knowledge translation actions are all submitted for approval to the SG Project team composed of Indigenous and non-Indigenous colleagues. In addition, non-Indigenous members of the SG Project, as myself, are regularly invited to meetings led by Indigenous members of the team to discuss practices leading to culturally safe research and cultural humility. As a sub-activity of the SG Project, the first Indigenous Background Variant Library informing on the common genomic variation of Indigenous people is being built. Once available, this new reference will improve clinical genomic sequencing efficiency and reduce the gap between Indigenous and non-Indigenous patients’ access to genetic diagnosis and precision medicine.

Currently, only ~30% of Indigenous families are receiving a genetic diagnosis. This may be due to: (1) lack of knowledge on normal/common variation in Indigenous people and/or (2) difficulty in detecting more complex variants using available clinical methods. As part of the Precision Diagnosis study, a sub-activity of the Silent Genomes Project, I work on the development of new approaches to detect hidden causes of genetic disease in these patients. Recently, we used the worm, Caenorhabditis elegans, as a model to test sequencing methods usually used and develop our own on genomes known to have complex variations (e.g. inversion of a part of a chromosome or two chromosomes exchanging a segment of DNA). We showed that using usual genome sequencing, we could reliably detect complicated variations. Importantly, we successfully applied these methods to undiagnosed rare disease patients and were able to identify previously missed variants of interest. However, interpreting the effect of such genomic changes and confirming its implication in the disease is challenging. While we continue applying our methods to genomes of undiagnosed patients, we propose to integrate knowledge on normal genetic variation in Indigenous people with gene expression analyses to facilitate the interpretation of complex genome disruptions.

As the first phase of the SG Project is coming to an end, we worked with ~100 Indigenous probands with a RD (89 families), for whom we attempt everything possible and beyond to identify the genetic cause of their syndrome. This mission is of the most importance as the discovery of causative mutations have wide implications for the patients and their families: i) it allows better care and focused treatment plan; ii) it allows enrolment in clinical trials; iii) it gives answers to the patient and the family and prognosis information, which helps them plan a future for their child and as a family; iv) it allows patients and families to connect with a group of patients for support and information; v) it makes patients and families eligible for genomic testing and reproduction counselling. Overall, my project contributes to improving the health of Indigenous children with rare diseases and the well-being of their relatives and communities