In paediatric hypertrophic cardiomyopathy, MYH7 mutations were associated with more frequent obstruction (p=0.024), while genotype-negative patients had higher LVEF (p=0.017).
Observational (n=126)
Does genotype influence CMR-derived cardiac phenotype in paediatric hypertrophic cardiomyopathy?
Distinct CMR-derived phenotypic differences exist across genetic subgroups in paediatric HCM, which may aid in risk stratification.
Abstract Background Paediatric hypertrophic cardiomyopathy (HCM) presents with variable phenotypic expression, influenced by the underlying genetic background. This study aimed to assess genotype-phenotype correlations using cardiac magnetic resonance (CMR) imaging at diagnosis in a cohort of paediatric patients. Methods 126 patients aged ≤18 years with sarcomeric or nonsyndromic familial HCM underwent CMR at diagnosis. Patients were categorized into four groups based on genetic findings: MYBPC3 (n=44), MYH7 (n=47), thin filament variants (TNNT2, TNNI3, or ACTC1) (n=19), and genotype-negative (n=16). Morphological and functional parameters were compared among groups. Results Median age was 12 IQR 10-15 years without significant difference between genotype (p=0.474). Patients with MYH7 mutations were more frequently obstructive compared to other genotypes (p=0.024). There was a trend towards higher prevalence of late gadolinium enhancement (LGE) in patients with thin filament variants and MYH7 (p=0.078). Genotype-negative patients exhibited higher left ventricular ejection fraction (LVEF) and cardiac output (LVCO) compared to other groups (p=0.017 and p=0.048, respectively). Conversely, patients with MYBPC3 mutations had larger indexed left ventricular end-systolic volume (LVESVi) (p=0.022). Conclusion This study highlights distinct CMR-derived phenotypic differences across genetic subgroups in paediatric HCM. MYH7 mutations were associated with a higher prevalence of left ventricular outflow tract obstruction, thin filament variants with increased fibrosis, while genotype-negative patients had higher LVEF. These findings may contribute to improved risk stratification and tailored management in paediatric HCM.
Bonanni et al. (2026) conducted an observational in Paediatric hypertrophic cardiomyopathy (HCM) (n=126). Genetic variants (MYBPC3, MYH7, thin filament variants, or genotype-negative) vs. Between-group comparisons was evaluated on Morphological and functional parameters on CMR. In paediatric hypertrophic cardiomyopathy, MYH7 mutations were associated with more frequent obstruction (p=0.024), while genotype-negative patients had higher LVEF (p=0.017).