Alkaptonuria
Alkaptonuria, or “black urine disease”, is a very rare inherited disorder that prevents the body from fully breaking down two protein building blocks (amino acids) called tyrosine and phenylalanine. It results in a build-up of a chemical called homogentisic acid in the body. This can turn urine and parts of the body a dark colour and lead to a range of problems over time. Amino acids are usually broken down in a series of chemical reactions. But in alkaptonuria, a substance produced along the way, homogentisic acid, cannot be broken down any further. This is because the enzyme that normally breaks it down does not work properly. Enzymes are proteins that make chemical reactions happen. It can build up in almost any area of the body, including the cartilage, tendons, bones, nails, ears and heart. It stains the tissues dark and causes a wide range of problems. People with this condition have a normal life expectancy, but with a lesser quality of life. There is currently no specific treatment or cure, but a certain diet is recommended to decrease the build up