A rare disease in which the urine turns black when exposed to air is known as Alkaptonuria. Accumulation of ochronosis, a dark pigment, which accumulates in the cartilage and the skin, causes this condition. People with this disease often fall prey to arthritis, which usually begins in adulthood. Heart problems and kidney stones are some of the other problems that can occur. Dark colored sweat, dark earwax and dark spots on the retina of the eye are some of the apparent symptoms. Mutations within the HGD gene can cause this condition. DNA testing is a diagnostic procedure.
HOW IS ALKAPTONURIA DIAGNOSED?
An estimate shows that Alkaptonuria affects 1 in every million people worldwide.