[Pathology of myxoid mitral valve degeneration: literature review and personal results].

Mitral prolapse is a parachute-like protrusion of the value into the left atrium. Almost always a myxoid degeneration of the valve is the base of such a prolapse. Myxoid degeneration is understood as dissolution of the collagenous fibrous layer and its replacement by acid glucosaminoglycans. An alteration of collagen is suspected as primary defect in this sometimes also inherited disorder. The electron microscope reveals fragmentation of collagen fibrils and elastic fibers and, within the myxoid material, free lysosomes, so called "matrix-vesicles". An isolated disturbance of collagen types I and III could not be detected by immunohistochemistry. Studies could also to date not demonstrate mutations in the genes coding for collagens.