Familial hypertrophic cardiomyopathy. Cardiac ultrasonic abnormalities in genetically affected subjects without echocardiographic evidence of left ventricular hypertrophy

Aims It is not known whether the apparent normality of echocardiographic examination results, in subjects bearing a mutation for hypertrophic cardiomyopathy but without ultrasonic left ventricular hypertrophy, is due to incomplete phenotypic expression, or inaccurate echocardiographic criteria. The aim of this study was to search for echocardiographic abnormalities in these patients. Methods and Results Echocardiography was performed in 100 subjects from two families with a mutation in the β-MHC (720) or My-BPC (714) genes. We compared genetically affected subjects with an apparently normal left ventricle (thickness