Abstract
Saguenay–Lac-Saint-Jean (SLSJ), a geographically isolated region in Quebec (Canada), harbors a genetically homogeneous population shaped by a triple founder effect and subsequent genetic drift. While founder autosomal recessive disorders are well documented in this population, the genetic basis of hereditary cardiovascular diseases (HCDs) remain underexplored. This study describes the development of a novel cardiogenetic care model and characterizes the regional genetic landscape of HCDs in SLSJ. From October 2014 to December 2024, two patient groups were evaluated at the Cardiogenetics Clinic: (1) individuals affected with cardiomyopathies, arrhythmias, or thoracic aortic disease; and (2) asymptomatic at-risk relatives undergoing predictive testing. Genetic investigations included multigene panel testing and targeted familial variant analysis. A longitudinal clinical database captured clinical and molecular data. The Cardiogenetics clinic evolved from a traditional one-on-one model into two scalable care pathways: the “Individual Trajectory” and the “Group Genetic Counseling Trajectory”. Over 10 years, 443 affected individuals and 294 at-risk relatives were assessed. Six recurrent pathogenic or likely pathogenic variants were identified across multiple unrelated, non-consanguineous French-Canadian families, consistent with allelic enrichment through genetic drift. The clinical database enabled genotype–phenotype correlation and informed cascade testing strategies. This tailored cardiogenetic care model improved access to timely genetic diagnosis, personalized risk management, and family-based preventive care. It presents a scalable framework applicable for other underserved populations and underscores the importance of integrating precision medicine into regional health systems. The identification of recurrent variants enhances understanding of the regional genetic etiology of HCDs and supports future screening efforts. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12687-026-00862-2.