Alkaptonuria

AKU; Alcaptonuria; Alkaptonuric ochronosis; Homogentisic acid oxidase deficiency; Homogentisic acidura; Ochronosis; Ochronotic arthritis

Alkaptonuria (black urine disease, alcaptonuria or ochronosis) is a rare inherited genetic disorder of tyrosine metabolism. This is an autosomal recessive trait that is caused by a defect in the enzyme homogentisic acid oxidase (EC 1.13.11.5). The enzyme normally breaks down a toxic tyrosine byproduct, homogentisic acid (also called alkapton), which is harmful to bones and cartilage and is excreted in urine. Symptoms A distinctive characteristic of alkaptonuria is that urine or ear wax ...