Functionally uni-leaflet mitral valves in a family: a case series.

Functionally uni-leaflet mitral valves are extremely rare. In severe cases, they are considered incompatible with life beyond the neonatal period. We present a case series of three adults with almost complete absence of the posterior mitral valve leaflet and who are asymptomatic, with no more than mild mitral regurgitation. We believe that this is the first reported instance of such findings in a single family.