Alkaptonuria is an inherited condition that is caused by a deficiency of the enzyme homogentisic acid (HGA) dioxygenase.
The three main features of alkaptonuria include
- ochronosis (bluish-black pigmentation in connective tissue),
- urine that turns black when exposed to air, and
- arthritis.
The discoloration of connective tissue usually begins after age 30. Other associated signs and symptoms can include
- heart problems,
- kidney stones,
- prostate stones, and
- discoloration of the earwax.
Cause of alkaptonuria
The condition results from an inherited mutation in the homogentisate 1,2-dioxygenase (HGD) gene. This condition is inherited in an autosomal recessive pattern, in which a mutation must be inherited from each parent to cause the condition.
Other alkaptonuria symptoms and signs
- Arthritis
- Discoloration of the Earwax
- Heart Problems
- Kidney Stones
- Ochronosis (Bluish-Black Pigmentation in Connective Tissue)
- Prostate Stones
- Urine That Turns Black When Exposed to Air
Main Article on Alkaptonuria Symptoms and Signs
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