The French hypertrophic cardiomyopathy gene register: A systematic large gene screening for hypertrophic cardiomyopathy

Background: Although the optimal approach is debated, systematic genetic screening for hypertrophic cardiomyopathy (HCM) is recommended. Aims: The performance of this approach was tested in GEREMY, a HCM prospective observational French register. Methods: Screening was based on a 12-gene panel, including the Fabry disease (GLA) and the transthyretin (TTR) genes. In case of a negative result and according to the clinical profile, 17–80 gene panels of were used. Results: A 748 adult cohort was examined: 68.9 % male, 54.6 ± 18.1 years, 27.5 % with a HCM family history, maximal wall thickness 19.1 ± 4.8 mm. Pathogenic or likely pathogenic variants were identified in 296 (39.6 %) patients, localized 1) in sarcomeric genes in 233, most frequently MYBPC3 (150) and MYH7 (42), with 24 identified only by large panels, with multiple variants in 8 patients and 2) in non-sarcomeric genes in 63, identified only with large panels in 26, predominantly TTR (26) and GLA(9), representing 8.8 % and 3.0 % of positive studies, respectively. Performance was 57.1 % before 40 years and 68.6 % in case of FH (vs otherwise 28.7 % and 26.1 % respectively, p < 0.001). In patients with a negative study, 148 had variants of unknown significance and 95 had senile or AL amyloidosis. Conclusions: Systematic genetic screening with a limited panel showed good performance, with diagnosis of Fabry disease (~1 %) and hereditary TTR amyloidosis (~3.5 %). Larger targeted panels were conclusive in 35.3 % of patients, of which 12 % had a negative initial approach.