Rare association of a patient with Alagille syndrome and mitral valve regurgitation.

A 9-year-old patient with known Alagille syndrome presented to our institution with progressive mitral valve regurgitation due to prolapse of the posterior valve leaflet. She underwent successful mitral valve replacement with a mechanical prosthesis 4 years after the initial diagnosis. To the best of our knowledge, an association between mitral valve regurgitation and Alagille syndrome has not been previously described.