[Hypertrophic cardiomyopathies]

Hypertrophic cardiomyopathy (CMH) is characterised by hypertrophy of the left ventricle, typically predominantly asymmetric on the interventricular septum. The dreaded complication of the disease is sudden death, especially on physical exertion, and this can constitute the first symptom of the disease. Classified as primary or idiopathic for a long time, there have been considerable recent advances in the molecular genetics which have allowed the physiopathology of the disease to be unveiled. There is great genetic heterogeneity but the different genes have in common a coding for sarcomere proteins. Functional studies suggest that the mutations entail a primary alteration of sarcomere function, with secondary and compensatory hypertrophy. The genetic data equally offer the opportunity to re-evaluate the natural history and the clinical spectrum of the disease. A better understanding of the disease, coming from these molecular data, has allowed a great improvement in the relevance of the information given to patients and their relatives during genetic counselling consultations. The performance of a genetic test with a medical aim can equally be discussed in certain specific situations.