Alkaptonuria

Jump to: navigation, search

For patient information click here

Alkaptonuria
Homogentisic acid.svg
Homogentisic acid
ICD-10 E70.2
ICD-9 270.2
OMIM 203500
DiseasesDB 409
MeSH D000474

WikiDoc Resources for Alkaptonuria

Articles

Most recent articles on Alkaptonuria

Most cited articles on Alkaptonuria

Review articles on Alkaptonuria

Articles on Alkaptonuria in N Eng J Med, Lancet, BMJ

Media

Powerpoint slides on Alkaptonuria

Images of Alkaptonuria

Photos of Alkaptonuria

Podcasts & MP3s on Alkaptonuria

Videos on Alkaptonuria

Evidence Based Medicine

Cochrane Collaboration on Alkaptonuria

Bandolier on Alkaptonuria

TRIP on Alkaptonuria

Clinical Trials

Ongoing Trials on Alkaptonuria at Clinical Trials.gov

Trial results on Alkaptonuria

Clinical Trials on Alkaptonuria at Google

Guidelines / Policies / Govt

US National Guidelines Clearinghouse on Alkaptonuria

NICE Guidance on Alkaptonuria

NHS PRODIGY Guidance

FDA on Alkaptonuria

CDC on Alkaptonuria

Books

Books on Alkaptonuria

News

Alkaptonuria in the news

Be alerted to news on Alkaptonuria

News trends on Alkaptonuria

Commentary

Blogs on Alkaptonuria

Definitions

Definitions of Alkaptonuria

Patient Resources / Community

Patient resources on Alkaptonuria

Discussion groups on Alkaptonuria

Patient Handouts on Alkaptonuria

Directions to Hospitals Treating Alkaptonuria

Risk calculators and risk factors for Alkaptonuria

Healthcare Provider Resources

Symptoms of Alkaptonuria

Causes & Risk Factors for Alkaptonuria

Diagnostic studies for Alkaptonuria

Treatment of Alkaptonuria

Continuing Medical Education (CME)

CME Programs on Alkaptonuria

International

Alkaptonuria en Espanol

Alkaptonuria en Francais

Business

Alkaptonuria in the Marketplace

Patents on Alkaptonuria

Experimental / Informatics

List of terms related to Alkaptonuria

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

Alkaptonuria (black urine disease, alcaptonuria 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.

Symptoms

A distinctive characteristic of alkaptonuria is that ear wax exposed to air turns red or black (depending on diet) after several hours because of the accumulation of homogentisic acid. Similarly, urine exposed to air can become dark; this is useful for diagnosising young children using diapers. It is also possible to develop a black discoloration of the nails. In adulthood, but usually not before age forty, persons suffering from alkaptonuria develop progressive arthritis (especially of the spine), due to the long-term buildup of homogentisate in bones and cartilage. The urine is malodorous.

Diagnosis

Presumptive diagnosis can be made by adding sodium or potassium hydroxide to urine and observing the formation of a dark brown to black pigment on the surface layer of urine within 30 minutes to 1 hour. Diagnosis can be confirmed by demonstrating the presence of homogentisic acid in the urine. This may be done by paper chromatography and thin-layer chromatography.

Treatment

Prevention is not possible and the treatment is aimed at ameliorating symptoms. Reducing intake of the amino acids phenylalanine and tyrosine to the minimum required to sustain health (phenylalanine is an essential amino acid) can help slow the progression of the disease.

History

Alkaptonuria was one of the four diseases described by Sir Archibald Edward Garrod, as being the result of the accumulation of intermediates due to metabolic deficiencies. He linked ochronosis with the accumulation of alkaptans in 1902,[1] and his views on the subject were summarised in a 1908 Croonian lecture at the Royal College of Physicians.[2] While Garrod identified it as a recessive condition, its genetic basis was not elucidated until 1996, when it was linked to HGO mutations.[3]

See also

References

  1. Garrod AE (1902). The incidence of alkaptonuria: a study in clinical individuality. Lancet 2: 1616−1620. Reproduced in Yale J Biol Med 75:221-31 (2002). PMID 12784973.
  2. Garrod AE (1908). The Croonian lectures on inborn errors of metabolism: lecture II: alkaptonuria. Lancet 2: 73–79.
  3. Fernández-Cañón JM, Granadino B, Beltrán-Valero de Bernabé D; et al. (1996). "The molecular basis of alkaptonuria". Nat. Genet. 14 (1): 19–24. doi:10.1038/ng0996-19. PMID 8782815.


de:Alkaptonurie fa:آلکاپتونوری hu:Alkaptonuria nl:Alkaptonurie


Linked-in.jpg