The focus of Dr. Kass' research program is the structure and function of ion channels that are expressed primarily in the heart. The laboratory most recently has focused on understanding the molecular physiology and pharmacology of congenital arrhythmias. These arrhythmias are caused by inherited mutations in genes coding for ion channels and/or ion channel related proteins expressed in the heart. This work has contributed to an understanding of gene-specific risk factors caused by mutation-induced changes in heart ion channel activity, and to the development of a mutation-specific approach to manage these disorders. The mutation-specific therapeutic strategy, verified in genotyped patients, has established the principle that two variants of the same genetic disorder require dramatically different therapeutic strategies for disease management based on biophysical properties of specific genetic lesions. This approach has evolved from close collaborations with clinical colleagues in which information is shared from clinic to basic laboratory and back to clinic. Additional studies are aimed at unraveling the structural basis of mutation-induced, and potentially lethal, disease phenotypes using approaches such as voltage-clamp fluorometry to directly measure movement of gating machinery in the ion channel of interest as well as biochemical methods of directly probing structures of region of ion channels that are hotspots for disease-causing mutations and the use of computer-based modeling to understand both structure and functional consequences of these mutations. The goal of this approach is to unmask new and specific targets for the development of anti-arrhythmic drugs.