Mitral valve prolapse can be caused by a variety of mechanisms. In most cases, it is harmless and does not cause symptoms or need to be treated. In a small number of cases, it can cause severe mitral regurgitation (leakage of blood back through the valve) and needs to be treated with surgery.

Some forms of mitral valve prolapse seem to be hereditary. Mitral valve prolapse has been associated with Marfan's syndrome (a disorder present from birth), Graves' disease, and other disorders.

Many people with mitral valve prolapse are thin women who may have minor chest wall deformities, scoliosis, or other disorders. There may also be an atrial septal defect (a hole in the wall that separates the left and right upper heart chambers) high in the wall of the heart (called an ostium secundum defect).