How is etiology of mitral regurgitation?

Disease of any of the five mitral valve apparatus (leaflets, annulus, chorodae tendinae, papillary muscles, subjacent myocardium. Acute mitral regurgitation (endocarditis, papillary muscle rupture post-MI, trauma, chordal rupture/leaflet flail (MVP/IE)) Chronic mitral regurgitation (myxomatous, RF, endocarditis, mitral annular calcification, congenital celft/AV canal, HOCM with SAM, ischemic LV remodeling, dilated cardiomyopathy, radiation)