Lamin A/C haploinsufficiency causes dilated cardiomyopathy and apoptosis-triggered cardiac conduction system disease.

Mutations in the lamin A/C (LMNA) gene, which encodes nuclear membrane proteins, cause a variety of human conditions including dilated cardiomyopathy (DCM) with associated cardiac conduction system disease. To investigate mechanisms responsible for electrophysiologic and myocardial phenotypes caused by dominant human LMNA mutations, we performed longitudinal evaluations in heterozygous Lmna(+/-) mice. Despite one normal allele, Lmna(+/-) mice had 50% of normal cardiac lamin A/C levels and developed cardiac abnormalities.

Cardiac electrophysiological characteristics of the mdx ( 5cv ) mouse model of Duchenne muscular dystrophy.

Background: Duchenne muscular dystrophy (DMD) is a progressive muscle disease caused by mutations in the dystrophin gene. Cardiomyopathy, conduction abnormalities, and ventricular arrhythmias are significant complications of this disease. The mdx ( 5cv ) mouse carries a dystrophin mutation and demonstrates a more severe phenotype than the classic mdx mouse.

Somatic events modify hypertrophic cardiomyopathy pathology and link hypertrophy to arrhythmia.

Sarcomere protein gene mutations cause hypertrophic cardiomyopathy (HCM), a disease with distinctive histopathology and increased susceptibility to cardiac arrhythmias and risk for sudden death. Myocyte disarray (disorganized cell-cell contact) and cardiac fibrosis, the prototypic but protean features of HCM histopathology, are presumed triggers for ventricular arrhythmias that precipitate sudden death events. To assess relationships between arrhythmias and HCM pathology without confounding human variables, such as genetic heterogeneity of disease-causing mutations, background genotypes, and lifestyles, we studied cardiac electrophysiology, hypertrophy, and histopathology in mice engineered to carry an HCM mutation.