Black aorta in a patient with alkaptonuria (ochronosis).

A rare cause of valvular heart disease is the deposition of foreign material in the valvular tissues, including material accumulating as a result of inborn errors of metabolism of the essential amino acids. Alkaptonuria can result in accumulation of homogentisic acid. We report the case of a patient with alkaptonuria undergoing surgery for aortic valve replacement.