DECIPHERING THE MOLECULAR-GENETICS OF CONGENITAL HEART-DISEASE

Congenital heart diseases are starting to benefit from the major advan ces provided by the advent of molecular biology methods. It is now pos sible to identify genes which are responsible for congenital heart dis eases. The gene responsible for supravalvular aortic stenosis - an aut osomal dominant trait - was cloned last year. It is the elastin gene. DiGeorge and Shprintzen syndromes, conotruncal anomaly face and some c ardiac malformations have a common cause: a deletion of the 22q11 regi on resulting in a monosomy. Although the region of deletion is large, it is possible that monosomy of only one gene results in these conditi ons. Studies are underway to evaluate the impact of this new genetic f actor on the incidence of congenital heart malformations. Studies on f amilial bundle branch block, and lateralization defect with midline an omalies are soon going to show a chromosomal region with the gene defe ct. Discovering the genes and their protein products which are implied in the cardiac morphogenesis will definitively change our understandi ng of these cardiac malformations.