What Causes Mitral Valve Prolapse?

The exact cause of mitral valve prolapse (MVP) isn't known. Most people who have the condition are born with it. MVP tends to run in families and is more common in people who were born with connective tissue disorders, such as Marfan syndrome.

The mitral valve can be abnormal in two ways. First, the valve flaps may be oversized and thickened. Second, the valve flaps may be "floppy." The tissue of the flaps and their supporting "strings" are too stretchy, and parts of the valve flop or bulge back into the atrium.

Some people's valves are abnormal in both ways. Either way can keep the valve from making a tight seal.