Mitral valve with a single leaflet.

Congenital anomalies of the mitral valve apparatus are rare. Of such cases, congenital mitral stenosis, atresia, accessory valvular tissue, and cleft mitral valve are more common. Descriptions of unileaflet mitral valves (either partial or complete leaflet agenesis/hypoplasia) are extremely rare and largely limited to a few case reports. We report herein a 45-year-old nulliparous woman presenting to our outpatient clinic with chest discomfort and dyspnea on minimal exertion. Mitral valve with a single leaflet leading to a significant obstruction in left ventricular outflow was seen on transthoracic echocardiography and confirmed with transesophageal two- (2D) and three-dimensional (3D) echocardiography. Metoprolol was prescribed to relieve obstruction and symptoms.