Alkaptonuria

**Definition:** An inborn error of amino acid metabolism resulting from a defect in the enzyme HOMOGENTISATE 1,2-DIOXYGENASE, an enzyme involved in the breakdown of PHENYLALANINE and TYROSINE. It is characterized by accumulation of HOMOGENTISIC ACID in the urine, OCHRONOSIS in various tissues, and ARTHRITIS.

**Tree numbers:** - C16.320.565.100.187 - C18.452.648.100.187

**Synonyms:** - Alcaptonuria - Homogentisic Acid Oxidase Deficiency - Homogentisic Acidura