EXPERIENCE FROM CLINICAL GENETICS IN HYPERTROPHIC CARDIOMYOPATHY - PROPOSAL FOR NEW DIAGNOSTIC-CRITERIA IN ADULT MEMBERS OF AFFECTED FAMILIES

The diagnosis of hypertrophic cardiomyopathy has relied on echocardiog raphic demonstration of unexplained left ventricular hypertrophy. The prevalence of hypertrophic cardiomyopathy defined in this way has been estimated to be 1:500 and experience indicates that these criteria ar e relatively specific when other causes of left ventricular hypertroph y are absent. In recent years, however, the systematic evaluation of p edigrees performed in the context of molecular genetic studies reveale d that in some families with hypertrophic cardiomyopathy up to 20% of adults who carry a disease causing gene defect do not fulfil conventio nal echocardiographic criteria. None the less, most of these individua ls show symptoms, electrocardiographic alterations, and/or minor echoc ardiographic abnormalities. Revised diagnostic criteria in members of families with hypertrophic cardiomyopathy are proposed, including majo r and minor criteria based on symptoms, and electrocardiographic and e chocardiographic abnormalities. Given that the chance of inheriting th e gene defect is 1:2, the likelihood that symptoms plus electrocardiog raphic or echocardiographic abnormalities are the expression of a dise ase causing gene is high.