GENETIC BASES OF ARRHYTHMIAS

We have long known that there are diseases which are inherited from th e parents, but it has not been until this last decade, with the introd uction of the techniques of molecular biology, that we have been able to study them. These techniques have enable us to localize and detect the gene that causes a disease in the members of a family. The identif ication of a disease-causing gene does not lead only to the diagnosis and possible treatment of a very select patient population (the one wi th the familial disease), but also to a better understanding of the mo lecular basis and pathogenesis of the nonfamilial forms of the disease . Cardiology, despite having received these techniques more slowly, is now completely. Involved in the study of the molecular basis of cardi ac diseases. The first Gene to be mapped was that of hypertrophic card iomyopathy in 1989. Since then, advances have been achieved at all lev els in familial cardiac diseases. Hypertension, atherosclerosis, conge nital heart diseases, and arrhythmias have all benefitted from the new techniques. Spectacular progress has been achieved in understanding f amilial heart rhythm disturbances, like long QT syndrome, both as cong enital and acquired diseases. In the last five years 4 loci and 3 gene s have been identified. The first studies of genetic based therapy hav e shown that in the near future patients with receive medication depen ding on the affected gene. Other familial arrhythmias are presently un der study. Loci have been detected in some, such as bundle branch bloc k and familial atrial fibrillation. At the speed that the techniques a re evolving, and with the impressive advances of the Human Genome Proj ect, we can expect to find the rest of the genes causing familial dise ases in the next few years. These results are encouraging and clearly indicate the need for genetic diagnosis in all patients with these dis eases. The diagnostic and therapeutic implications of all these discov eries could be of paramount importance.