Cardiomyopathies are categorized as extrinsic, being caused by external factors, such as hypertension, ischemia,
inflammation, valvular dysfunction, or as intrinsic, which correspond to myocardial diseases without identifiable
external causes. These so called primary cardiomyopathies can be categorized in four main forms: hypertrophic, dilated,
restrictive, and arrhythmogenic right ventricular cardiomyopathy. Cardiomyopathies are diagnosed by clinical expression,
echocardiography, electrocardiography, non-invasive imaging, and sometimes by cardiac catheterization to rule out external
causes as ischemia. The two main forms of primary cardiomyopathies are the hypertrophic and dilated cardiomyopathies.
Most of hypertrophic cardiomyopathy and 20-50% of dilated cardiomyopathy are familial showing a wide
genetic and phenotypic heterogeneity. This review presents the current knowledge on the causative genes, molecular
mechanisms and the genotype–phenotype relations of hypertrophic and dilated cardiomyopathies.