Molecular Genetic Studies in Atrial Fibrillation

Atrial fibrillation is a complex disease. Its etiologies are diverse and genetic factors may also contribute to this disease. With the advent of modern molecular biology technology, it is now possible to explore the genetic components in the pathogenesis of atrial fibrillation. Past molecular genetic studies on atrial fibrillation in the literature can be divided into linkage analysis studies and association studies. The subjects for linkage analysis studies are pedigrees of probands with Mendelian hereditary atrial fibrillation. The first locus identified for autosomal dominant atrial fibrillation locates at 10q22–q24. However, the exact gene is still unknown. Another linkage analysis study in Chinese revealed that LQT1 gene (I<sub>Ks</sub> α-subunit) was the responsible gene. A missense mutation in the I<sub>Ks</sub> α-subunit results in a gain of function, which is important in causing atrial fibrillation. The third known locus for familial atrial fibrillation locates at 6q14–16. The responsible gene remains still unknown. The other type of studies takes the case-control design (association studies) and the subjects have multigenic atrial fibrillation. In