Alkaptonuria usually causes painful joint disease involving the back, hips, and knees.
It also can cause bones to break easily, dangerous hardening of heart valves, formation of prostate and kidney stones, and the appearance of dark spots in the white part of the eyes and on the ear. Alkaptonuria is a genetic disease. It is present from birth, but may not produce symptoms until early to mid-adulthood. Although most people with Alkaptonuria are able to live normal life spans, the disease is often painful and disabling later in life. People all over the world can have Alkaptonuria.