1. From the Experimental and Molecular Cardiology Group (C.R.B., A.A.M.W.), the Department of Clinical Genetics (C.R.B., M.M.A.M.M.), the Department of Cardiovascular Pathology (A.C.v.d.W.), and the Department of Pediatric Cardiology (J.L.), Academic Medical Center, Amsterdam, and the Department of Medical Physiology (M.B.R., W.A.G., L.J.H., H.J.), University Medical Center, Utrecht, The Netherlands.