Hypertrophic cardiomyopathy: from molecular and genetic mechanisms to clinical management
Department of Cardiovascular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, U.K.
1 Correspondence: Hugh Watkins, Department of Cardiovascular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DV, U.K.
Abstract
Molecular genetic research in hypertrophic cardiomyopathy (HCM) has shown that this heart muscle disorder, which was previously considered `idiopathic', is caused by a wide diversity of mutations that affect the cardiac contractile proteins. With this information, it is now possible to explore molecular genetic diagnosis, recalibration of clinical diagnostic tools and criteria, and genotype-phenotype correlations. However, the biggest potential benefit is that a detailed understanding of the disease pathway may lead to disease-modifying treatments. Demonstration of the mutations in cardiac contractile protein genes has focused attention on alterations in contractility. However, no unifying abnormality of contractility is apparent; rather, the defects point to an inefficiency of ATP usage in the sarcomere. The very recent finding of HCM-causing mutations in a regulatory subunit of AMP-activated protein kinase strongly supports the hypothesis that the unifying abnormality in this condition is an inability to maintain normal ATP availability in the myocardium during times of stress. This conclusion should ultimately lead to new approaches to therapy and to further consideration of the role of altered myocardial energetics in other forms of heart muscle disease.
Key Words: AMP kinase • cardiomyopathy • contractile proteins • energetics • genes