Mitral valve prolapse and ophthalmoplegia: a progressive, cardioneurologic syndrome.

Disorders characterized by both neurologic (ataxia, ophthalmoplegia, ptosis, neuromyopathy) and cardiologic (heart block, cardiomyopathy) abnormalities have been previously called the "ophthalmoplegia plus" syndromes. Most are not due to a specific enzyme defect or metabolic abnormality and thus may be similar phenotypic expressions of diverse causes. We studied seven patients with progressive external ophthalmoplegia and variable ataxia, with mitral valve prolapse and mitral regurgitation that progressed in severity as did the neuromuscular manifestations. Abnormal skeletal muscle biopsies showed "ragged-red" fibers or congenital fiber type disproportion; serum alanine levels were elevated; in-vivo and in-vitro tests of pyruvate metabolism gave abnormal results; C4 complement was decreased; and the patients' fibroblasts bound immunoglobulin when incubated with autologous serum. These data suggest a distinct neuromuscular disorder with metabolic and immunologic features associated with mitral valve prolapse and progressive mitral regurgitation.