Several heart defects seem to be caused by blocked flow of blood from heart. These includes aortic stenosis, mitral stenosis, coarctation of the aorta, bicuspid aortic valve, Shone complex, mitral valve atresia, interrupted aortic arch, and hypoplastic left heart syndrome. Together, we call these defects Left Ventricular Outflow Tract (LVOT) Obstruction. A block in blood flow can lead to under-development of the main pumping chamber of the heart called the left ventricle. We know that heart defects can occur more than once in a family. A way to find genes that cause heart defects is to compare members of families. Researchers at Baylor College of Medicine are conducting research on LVOTO and are recruiting children and adults with this condition and their close relatives. Participants are asked to provide a small blood or saliva sample at the time of enrollment, and a brief medical history and family history for heart diseases will be obtained. Your participation in this study will help us understand the genetic basis of these heart defects.