Alkaptonuria, also called black urine disease, is a rare inherited disorder caused by a missing enzyme that prevents the body from properly breaking down two amino acids: tyrosine and phenylalanine.
This causes a build-up of a chemical called homogentisic acid which can turn urine and parts of the body black or a dark color. The earliest sign is urine on diapers turning black after exposure to air for a few hours. Sometimes this sign is missed or overlooked and the disorder may go unnoticed until a person reaches their late 20s to early 30s.
In adults, homogentisic acid can slowly build up in tissues, bones, nails, cartilage, and tendons, staining them dark. Brown or black spots may develop on the whites of people's eyes; ear cartilage may thicken and look blue, grey, or black; ear wax may be black or reddish-brown. Joint pain may be experienced by those in their 30s, which progressively worsens and may lead to joint and spinal damage.
Currently, the only FDA approved treatment for alkaptonuria is Harliku (nitisinone).
Note: There are currently no drugs listed for "Alkaptonuria".
