ELN and mitral valve prolapse: In addition, mitral valve prolapse may also be observed.16 Aortic root dilation was found in 60% of a series of patients with Marfan's syndrome (74% males, 33% females) while mitral valve prolapse was found in 91% (87% males, 100% females).13 The histopathology of the aortic wall is characterized by widespread fragmentation of the elastin component, and the elastin fibers are often thin.