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The Mouse Adult Gross Anatomy Ontology and Mammalian Phenotype Ontology are downloaded weekly from the Mouse Genome Informatics databases at Jackson Laboratories ( For more information about these ontologies, see the MGI Publications Page at

Term:homogentisic aciduria
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Accession:MP:0030619 term browser browse the term
Definition:excretion of excessive amounts of homogentisic acid (an intermediate in the tyrosine degradation pathway) and its oxidized form (benzoquinoneacetate) in the urine, giving it an unusually dark color on prolonged exposure to air
Comment:Homogentisic aciduria is one of the three distinct clinical features of alkaptonuria (AKU), along with ochronosis and ochronotic osteoarthropathy; the darkening of urine occurs because the HGA pigment oxidizes to benzoquinoneacetate (BQA), which forms a melanin-like polymer that slowly turns urine black {xref="PMID:8188247", xref="PMID:25003018"}
Synonyms:exact_synonym: increased urine homogentisic acid level

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  mammalian phenotype 5415
    renal/urinary system phenotype 649
      abnormal renal/urinary system physiology 478
        abnormal urine homeostasis 380
          aciduria 3
            homogentisic aciduria 0
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