Altered collagen composition in a prolapsing mitral valve with ruptured chordae tendineae.

A patient presented with mitral valve prolapse, ruptured chordae tendineae, severe mitral regurgitation and congestive heart failure. Pathologic studies demonstrated myxomatous changes of both mitral leaflets. Collagen analysis of the valve and of the chordae tendineae revealed the presence of type I collagen in normal quantities and a striking absence of type III and AB collagens. The altered collagen in this patient's mitral valve probably contributed to the development of his mitral valve disorder.