Abstract
Background: The spectrum of genetic variants and their clinical significance of Hypertrophic cardiomyopathy (HCM) have been poorly studied in Asian patients. The objectives of this study were to assess the spectrum of genetic variants and genotype–phenotype relationships within a Korean HCM population. Methods: Eighty-nine consecutive unrelated HCM patients were included. All patients underwent genotypic analysis for 23 HCM-associated genes. Clinical parameters including echocardiographic and cardiac magnetic resonance (CMR) parameters were evaluated. A composite of major adverse cardiac and cerebrovascular events was assessed. Results: Genetic variants were detected in 55 of 89 subjects. Pathogenic variants or likely pathogenic variants were identified in 27 of HCM patients in MYBPC3, TNNI3, MYH7, and MYL7. Variants of uncertain significance were identified in 28 patients. There were significant differences in the presence of non-sustained ventricular tachycardia (p = 0.030) and myocardial fibrosis on CMR (p = 0.029) in the detected compared to the not-detected groups. Event-free survival was superior in the not-detected group (p = 0.006). Conclusion: Genetic variants in patients with HCM are relatively common and are associated with adverse clinical events and myocardial fibrosis on CMR. Genotypic analysis may add important information to clinical variables in the assessment of long-term risk for HCM patients.
Highlights
Hypertrophic cardiomyopathy (HCM) is a genetic heart disease with an estimated prevalence of 0.2% of the global population [1]
The aims of this study were to understand the distribution of genetic variants among Korean HCM patients and to link their clinical and imaging phenotypic characteristics by genotype status
Inclusion criteria were (i) end-diastolic left ventricular (LV) wall thickness of ≥15 mm in any site or LV septal thickness:posterior wall thickness ≥ 1.3 with the absence of any underlying condition that may be associated with LV hypertrophy; (ii) end-diastolic LV septal thickness:posterior wall thickness ≥1.5 in patients with systemic hypertension; or (iii) LV hypertrophy confined to the LV apex with maximal apical wall thickness of ≥15 mm or a ratio of maximal apical to posterior wall thickness of ≥1.3 at end-diastole, regardless of the presence of systemic hypertension [7,11,12,13]
Summary
Hypertrophic cardiomyopathy (HCM) is a genetic heart disease with an estimated prevalence of 0.2% of the global population [1]. With advances in techniques for genotypic analysis and tools for clinical evaluation such as cardiac magnetic resonance (CMR) imaging, which provides accurate information on LV morphology and information on the amount and pattern of myocardial fibrosis in HCM [9,10], novel approaches for the evaluation of genotypic–phenotypic associations and risk evaluation in HCM are required. The spectrum of genetic variants and their clinical significance of Hypertrophic cardiomyopathy (HCM) have been poorly studied in Asian patients. Conclusion: Genetic variants in patients with HCM are relatively common and are associated with adverse clinical events and myocardial fibrosis on CMR. Genotypic analysis may add important information to clinical variables in the assessment of long-term risk for HCM patients
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