<unk>  (black urine disease,<unk>  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.
Alkaptonuria
Homocystinuria
Glycosuria
Mevalonic aciduria
Essential fructosuria
Phenylketonuria
Cystinuria
Xanthinuria