The purpose of this study is to gain a better understanding of alkaptonuria and collect medical data on patients who may later participate in new drug trials for this rare genetic disease. In alkaptonuria, a pigment called homogentisic acid collects in bone and connective tissue, causing arthritis and eventually bone fractures, and also causes discoloration in the ears and whites of the eyes. Some patients also develop kidney stones and heart valve problems. Alkaptonuria has not been studied for decades; and scientists expect to gain comprehensive clinical information using current medical techniques.