alkaptonuria


Also found in: Dictionary, Thesaurus, Encyclopedia, Wikipedia.

alkaptonuria

 [al-kap″to-nu´re-ah]
an autosomal recessive aminoacidopathy characterized by accumulation of homogentisic acid. It is manifested by elevated concentrations of homogentisic acid in the urine (which darkens on standing or with alkalinization), a peculiar discoloration of body tissues known as ochronosis, and arthritis.

al·cap·ton·u·ri·a

, alkaptonuria (al-kap-ton-yū'rē-ă), [MIM*203500]
Excretion of homogentisic acid (alkapton) in the urine resulting from congenital lack of the enzyme homogentisate 1,2-dioxygenase, which mediates an essential step in the catabolism of phenylalanine and tyrosine; urine turns dark if it is allowed to stand or is alkalinized (a result of formation of polymerization products of homogentisic acid); frequently occurs throughout relatively long periods or may appear at irregular intervals; arthritis and ochronosis are late complications; autosomal recessive inheritance; caused by mutation in the homogentisate 1,2-dioxygenase gene (HGD) on chromosome 3q.
[alkapton + G. ouron, urine]

alkaptonuria

or

alcaptonuria

(ăl-kăp′tə-no͝or′ē-ə)
n.
An inherited disorder that affects phenylalanine and tyrosine metabolism and leads to the excretion of homogentisic acid in the urine.

alkaptonuria

Black pain disease, black urine disease, alcaptonuria, alcaptonuric ochronosis An AR defect in tyrosine and phenylalanine metabolism, more common in ♂, due to homogentisic acid oxidase–HAO deficiency; metabolic pathway of phenylalanine and tyrosine → ring opening of homogentisic acid → malylacetoacetic acid; alkaptonuria is first recognized by the mother who cannot clean the children's diaper as the urine oxidizes to a pitch black color upon exposure to air Clinical Arthritis due to homogentisic acid deposition in cartilage, tendons, as well as in the sclera, viscera, skin; when severe, pigment deposition can compromise cardiac, renal, or pulmonary function, and spill into the urine as a melanin-like substance. Cf Blue diaper syndrome.

al·cap·to·nu·ri·a

, alkaptonuria (al-kap'tŏ-nyūr'ē-ă)
Excretion of homogentisic acid (alkapton) in the urine due to congenital lack of the enzyme homogentisate 1,2-dioxygenase; urine turns dark if allowed to stand; may recur and subside at irregular intervals; arthritis and ochronosis are late complications.
[alkapton + G. ouron, urine]

alkaptonuria

A genetic disease in which a gene mutation on chromosome 3 results in a defective enzyme that leads to the accumulation of a coloured polymer molecule homogentisic acid. This binds to the COLLAGEN of cartilage, making it brittle and easily worn away. The result is a form of OSTEOARTHRITIS. In alkaptonuria, the urine turns black on exposure to light or alkali.

alkaptonuria

see GARROD,A.E.

alkaptonuria 

A rare, hereditary, metabolic disorder characterized by dark urine. It is caused by mutation in the homogentisate 1, 2-dioxygenase gene (HGD), which produces an error in the metabolism of the amino acids tyrosine and phenylalanine, which normally break down by oxidation to homogentisic acid. However, in this condition homogentisic acid is not broken down but stored in tissues, especially cartilage, which it turns bluish-black, and excreted in the urine. Ocular signs are pigmentation of the sclera, most markedly near the insertions of the recti muscles, and of the cornea and conjunctiva.
References in periodicals archive ?
Sadly it was only a temporary reprieve as the trial did not yield enough results to get the drug approved for treating alkaptonuria.
Alkaptonuria (AKU) is classed as an ultra rare disease affecting around one in 250,000 to one in a million people worldwide.
Alkaptonuria: Effects of Physical Therapy in The Treatment of Low Back Pain.
We searched PubMed for articles published between 1974 and 2017 using the search terms "alkaptonuria", "ochronosis", "ochronotic arthropathy", "ochronotic tendinopathy", and "alkaptonuria and osteoporosis." We also checked the references in the retrieved articles.
[14.] Alkaptonuria, US National Library of Medicine, Medicine Plus.
Keywords: Alkaptonuria; lumbar disc hernia; ochronosis.
First described by Sir Archibald Garrod in 1902, alkaptonuria is the prototypical inborn error of metabolism, and the first disorder to conform to the principles of Mendelian recessive inheritance (1).
However, pathological tissue pigmentation is occasionally induced under several specific conditions, including ochronotic arthritis accompanied by alkaptonuria [1-3], haemosiderosis [4], and the use of drugs for Parkinson's disease [5, 6] or antibiotics [7-9].
Alkaptonuria (AKU) is an extremely rare autosomal recessive metabolic disorder characterized by a triad of homogentisic aciduria, arthritis, and ochronosis, affecting only 2–5 in a million individuals.[sup][1] The management of AKU is usually symptomatic.
INTRODUCTION: 'Ochronosis' literally meaning 'ochre or yellow appearance' (of the cartilage) was term used by Virchow to describe the musculoskeletal manifestation of alkaptonuria. Alkaptonuria is a rare autosomal recessive metabolic disorder.
A recent animal model of alkaptonuria brought further evidence in favor of nitisinone for the prevention of the development of ochronotic arthropathy [64].