Related Experiment Videos
Aetiology and pathogenesis of hypertrophic cardiomyopathy
1Department of Clinical Medicine, Cardiovascular and Immunological Sciences, Federico II University of Naples, Naples, Italy.
Insights
Hypertrophic cardiomyopathy, a genetic heart disorder, stems from mutations in sarcomeric protein genes. These mutations impair heart muscle function, leading to compensatory changes and varied symptoms.
Area of Science:
- Cardiovascular Genetics
- Molecular Cardiology
- Genetic Pathology
Background:
- Hypertrophic cardiomyopathy (HCM) is an autosomal dominant cardiac disorder.
- Characterized by myocyte hypertrophy, disarray, fibrosis, and small vessel disease.
- Over 100 mutations in ten genes encoding sarcomeric proteins are implicated.
Purpose of the Study:
- To elucidate the genetic basis and pathogenesis of hypertrophic cardiomyopathy.
- To understand the relationship between sarcomeric protein gene mutations and disease phenotype.
- To explore the mechanisms underlying phenotypic variability in HCM.
Main Methods:
- Genetic analysis to identify mutations in sarcomeric protein genes.
- Phenotypic characterization using clinical, electrocardiographic, and echocardiographic data.
- Pathological examination of cardiac tissue to assess myocyte structure and fibrosis.
Main Results:
- Identified over 100 mutations in ten sarcomeric protein genes responsible for HCM.
- Commonly implicated genes include beta-myosin heavy chain, myosin binding protein-C, and cardiac troponin T.
- Observed significant variability in clinical manifestations, irrespective of specific mutations, suggesting environmental or genetic modifiers.
Conclusions:
- Pathological cardiac changes in HCM are likely a compensatory response to impaired myocyte function.
- Mutations in sarcomeric proteins disrupt sarcomere function, triggering compensatory pathways similar to pressure overload hypertrophy.
- The pathogenesis involves impaired myocyte contractility leading to trophic factor release and characteristic anatomical changes.
Unlabelled:
The term hypertrophic cardiomyopathy is used to describe an autosomal dominant cardiac disorder, characterized by myocyte hypertrophy and disarray, interstitial fibrosis and small vessel disease, with or without macroscopic hypertrophy. More than 100 mutations in ten genes, all encoding sarcomeric proteins, have been identified as responsible for this disease. Mutations in the genes for beta-myosin heavy chain, myosin binding protein-C, and cardiac troponin T are the most common. Other genes involved are alpha-tropomyosin, cardiac troponin-I, essential and regulatory light chains, alpha-cardiac actin, titin, and alpha-myosin heavy chain. Some mutations are more frequently associated with a given phenotype, but no particular phenotype is mutation specific; in fact, some mutations exhibit highly variable clinical, electrocardiographic and echocardiographic manifestations. This variability in the phenotypic manifestations is probably due to the influence of environmental factors and/or modifier genes. While the aetiology of hypertrophic cardiomyopathy has been extensively elucidated, its pathogenesis is not completely understood. Mutated proteins are incorporated in the sarcomere and impair myocyte contractility. This probably triggers the compensatory local release of trophic factors, which influence the development of the typical anatomical features of the disease, with a pathway similar to that observed in secondary, pressure overload hypertrophy.
Conclusions:
The various pathological cardiac changes seen in hypertrophic cardiomyopathy are probably due to a compensatory response to impaired myocyte function resulting from mutations in the genes encoding sarcomeric proteins.