Molecular genetics of the Long QT syndrome

Long QT syndrome (LQT) is a cardiovascular disorder that causes syncope, seizures and sudden death. Two forms of inherited LQT have been identified, autosomal dominant and autosomal recessive. The autosomal dominant form is the most common form and is not associated with other known phenotypic abnormalities. Autosomal recessive LQT is associated with congenital neural deafness. The symptoms of LQT result from cardiac arrhythmias, specifically ventricular tachyarrhythmias, like torsade de pointes and ventricular fibrillation. In 1991, a gene for autosomal dominant LQT was localized to chromosome 11p15.5 (LQT1) in our laboratory. We employed linkage analyses, using PCR-based polymorphic markers regularly spaced throughout the human genome, to identify two new loci for autosomal dominant LQT-7q35-36 (LQT2) and 3p21-24 (<>LQT3