Genetic relevance and determinants of mitral leaflet size in hypertrophic cardiomyopathy

Abstract

Abstract Background Whether mitral leaflet elongation is a primary phenotype of hypertrophic cardiomyopathy (HCM) is controversial. We investigated the genetic relevance and determinants of mitral leaflet size by performing extensive gene analyses in patients with HCM. Methods Anterior mitral leaflet (AML) lengths were measured in HCM patients (n = 211) and age- and sex-matched controls (n = 30) using echocardiography with hemodynamic and chamber geometric assessments. We analyzed 82 nuclear DNA (8 sarcomeric genes, 74 other HCM-associated genes) and mitochondrial DNA. Cardiac magnetic resonance imaging (CMR) was performed in the 132 HCM patients. Results Average indexed AML was significantly longer for HCM than for controls (17.2 ± 2.3 vs. 13.3 ± 1.6 mm/m2, P 0.05). Conclusion AML elongation was a unique finding of HCM. However, the leaflet size was more related to chamber geometry and hypertrophy pattern rather than genetic factors within overt HCM.

Keywords

• Hypertrophic cardiomyopathy
• Mitral valve
• Mitral leaflet
• Gene