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Ochronosis is a disease characterized by the accumulation of homogentisic acid.

Alcaptonuria is a specific genetic defect that causes ochronosis.[1]


It is subclassified as:

  • Endogenous (genetic).
  • Exogenous.

The endogenous form is genetic and autosomal recessive.[2]


  • Tissue with blue-grey discolourization.[3]
  • Dark urine (after exposure to sunlight).




  • Deposits of (acellular) brown pigment (H&E sections) - key feature.
    • May be dark magenta.


See also


  1. Online 'Mendelian Inheritance in Man' (OMIM) 203500
  2. Turgay, E.; Canat, D.; Gurel, MS.; Yuksel, T.; Baran, MF.; Demirkesen, C. (Dec 2009). "Endogenous ochronosis.". Clin Exp Dermatol 34 (8): e865-8. doi:10.1111/j.1365-2230.2009.03618.x. PMID 20055850.
  3. 3.0 3.1 3.2 Baeva, M.; Bueno, A.; Dhimes, P.. "AIRP best cases in radiologic-pathologic correlation: ochronosis.". Radiographics 31 (4): 1163-7. doi:10.1148/rg.314105175. PMID 21768245.
  4. Fisher, AA.; Davis, MW. (Nov 2004). "Alkaptonuric ochronosis with aortic valve and joint replacements and femoral fracture: a case report and literature review.". Clin Med Res 2 (4): 209-15. PMID 15931360.
  5. URL: http://www.dermpedia.org/conference/wwwdermatopathologyconsultationscom?page=40. Accessed on: 1 February 2013.