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Encyclopedia > Alkaptonuria
Alkaptonuria
Classification & external resources
Homogentisic acid
ICD-10 E70.2
ICD-9 270.2
OMIM 203500
DiseasesDB 409
eMedicine ped/64 
MeSH D000474

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. Image File history File links Homogentisic_acid. ... Melanic acid is the common name chosen by William Prout for 2,5-dihydroxyphenylacetic acid. ... The International Statistical Classification of Diseases and Related Health Problems (most commonly known by the abbreviation ICD) provides codes to classify diseases and a wide variety of signs, symptoms, abnormal findings, complaints, social circumstances and external causes of injury or disease. ... The International Statistical Classification of Diseases and Related Health Problems 10th Revision (ICD-10) is a coding of diseases and signs, symptoms, abnormal findings, complaints, social circumstances and external causes of injury or diseases, as classified by the World Health Organization (WHO). ... // E00-E35 - Endocrine diseases (E00-E07) Disorders of thyroid gland (E00) Congenital iodine-deficiency syndrome (E01) Iodine-deficiency-related thyroid disorders and allied conditions (E02) Subclinical iodine-deficiency hypothyroidism (E03) Other hypothyroidism (E030) Congenital hypothyroidism with diffuse goitre (E031) Congenital hypothyroidism without goitre (E032) Hypothyroidism due to medicaments and other... The International Statistical Classification of Diseases and Related Health Problems (most commonly known by the abbreviation ICD) provides codes to classify diseases and a wide variety of signs, symptoms, abnormal findings, complaints, social circumstances and external causes of injury or disease. ... The following is a list of codes for International Statistical Classification of Diseases and Related Health Problems. ... The Mendelian Inheritance in Man project is a database that catalogues all the known diseases with a genetic component, and - when possible - links them to the relevant genes in the human genome. ... The Disease Bold textDatabase is a free website that provides information about the relationships between medical conditions, symptoms, and medications. ... eMedicine is an online clinical medical knowledge base that was founded in 1996. ... Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. ... Tyrosine (from the Greek tyros, meaning cheese, as it was first discovered in 1846 by German chemist Justus von Liebig in the protein casein from cheese[1][2]), 4-hydroxyphenylalanine, or 2-amino-3(4-hydroxyphenyl)-propanoic acid, is one of the 20 amino acids that are used by cells... It has been suggested that this article or section be merged into Dominance relationship. ... Ribbon diagram of the enzyme TIM, surrounded by the space-filling model of the protein. ... Homogentisate 1,2-dioxygenase is an enzyme which catalyzes the conversion of homogentisate to 4-maleylacetoacetate. ... The Enzyme Commission number (EC number) is a numerical classification scheme for enzymes, based on the chemical reactions they catalyze. ... Melanic acid is the common name chosen by William Prout for 2,5-dihydroxyphenylacetic acid. ...

Contents

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. 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. Arthritis (from Greek arthro-, joint + -itis, inflammation; plural: arthritides) is a group of conditions where there is damage caused to the joints of the body. ...


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. Melanic acid is the common name chosen by William Prout for 2,5-dihydroxyphenylacetic acid. ...


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. Phenyl alanine is an α-amino acid with the formula HO2CCH(NH2)CH2C6H5. ... Tyrosine (from the Greek tyros, meaning cheese, as it was first discovered in 1846 by German chemist Justus von Liebig in the protein casein from cheese[1][2]), 4-hydroxyphenylalanine, or 2-amino-3(4-hydroxyphenyl)-propanoic acid, is one of the 20 amino acids that are used by cells...


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] Sir Archibald Edward Garrod was an English physician who pioneered the field of inborn errors of metabolism. ... Ochronosis is a dermatological disorder that results in the adverse pigmentation of cartilage from a long term buildup of phenylalanine or tyrosine. ... College building by Denys Lasdun The Royal College of Physicians of London is the oldest medical institution in England was founded in 1518 and is one of the most active of all medical professional organisations. ...


See also

Ochronosis is a dermatological disorder that results in the adverse pigmentation of cartilage from a long term buildup of phenylalanine or tyrosine. ... Tyrosinemia (or Tyrosinaemia) is an error of metabolism, usually inborn, in which the body can not effectively break down the amino acid tyrosine, found in most animal and plant proteins. ...

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. 

A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ...

External links


  Results from FactBites:
 
Alkaptonuria - Wikipedia, the free encyclopedia (217 words)
Alkaptonuria also known as 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).
A distinctive characteristic of alkaptonuria is that urine exposed to air turns dark (or fl) after several hours because of the homogentisic acid.
  More results at FactBites »


 
 

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