Cardiovascular ochronosis: a case report and review of the medical literature.

Ochronosis is a rare disorder of tyrosine metabolism due to a deficiency of the enzyme homogentisic acid oxidase. The most common clinical manifestations include alkaptonuria, spondyloarthropathy, large joint arthritides and pigmentation of cartilage. Cardiac involvement may occur due to the deposition of polymerized homogentisic acid in the aortic, mitral and pulmonic valves. Usually, this leads to increasing rigidity and calcification. The only functionally significant valve lesion reported appears to be aortic stenosis. A possible link between ochronosis and coronary artery disease has been postulated. Further, a link between peripheral vascular disease and ochronosis may be present. We describe a case of ochronotic cardiovascular disease and review the literature on the subject.