Clinical applicability of molecular biology: the case of the long QT syndrome

The clinical applicability of molecular cardiology has been questioned at length and by many clinical investigators. The congenital long QT syndrome (LQTS) provides an excellent example of how tight the relationship can be between molecular biology and clinical cardiology. The advent of molecular diagnosis has demonstrated how low the penetrance can be in LQTS; this implies that there are many gene carriers who do not show the clinical phenotype and may have a normal QT interval despite being at risk. There is also a gene-specific predisposition to be at risk for cardiac arrest under different circumstances, and this provides additional basis for a gene-specific approach to therapy.