alkaptonuria
Sign in to saveAlkaptonuria is a rare inherited genetic disease which is caused by a mutation in the HGD gene for the enzyme homogentisate 1,2-dioxygenase (); if a person inherits an abnormal copy from both parents (it is a recessive condition), the body accumulates an intermediate substance called homogentisic acid in the blood and tissues. Homogentisic acid and its oxidized form alkapton are excreted in the urine, giving it an unusually dark color. The accumulating homogentisic acid causes damage to cartilage (ochronosis, leading to osteoarthritis) and heart valves, as well as precipitating as kidney stone
Key facts
- Medical condition (new).name
- Alkaptonuria
- Medical condition (new).synonyms
- Black urine disease, black bone disease, alcaptonuria
- Medical condition (new).image
- OCHRONOSIS.jpg
- Medical condition (new).caption
- Pigmentation of the face in alkaptonuria
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Article
12 sectionsContents
- Signs and symptoms
- Pathophysiology
- Diagnosis
- Treatment
- Prognosis
- Epidemiology
- History
- Society and culture
- Research directions
- See also
- References
- External links
Alkaptonuria is a rare inherited genetic disease which is caused by a mutation in the HGD gene for the enzyme homogentisate 1,2-dioxygenase (); if a person inherits an abnormal copy from both parents (it is a recessive condition), the body accumulates an intermediate substance called homogentisic acid in the blood and tissues. Homogentisic acid and its oxidized form alkapton are excreted in the urine, giving it an unusually dark color. The accumulating homogentisic acid causes damage to cartilage (ochronosis, leading to osteoarthritis) and heart valves, as well as precipitating as kidney stones and stones in other organs. Symptoms usually develop in people over 30 years old, although the dark discoloration of the urine is present from birth.
Apart from treatment of the complications (such as pain relief and joint replacement for the cartilage damage), the drug nitisinone has been found to suppress homogentisic acid production, and research is ongoing as to whether it can improve symptoms. Alkaptonuria is a rare disease; it occurs in one in 250,000 people, but is more common in Slovakia and the Dominican Republic.