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Alkaptonuria is a rare condition in which a person's urine turns a dark brownish-black color when exposed to air.
See also: Inborn error of metabolism
Alternative NamesAKU; Alcaptonuria; Homogentisic acid oxidase deficiency; Alcaptonuric ochronosis
Causes, incidence, and risk factorsA defect in the HGD gene causes alkaptonuria.
The gene defect makes the body unable to properly break down certain amino acids (tyrosine and phenylalanine). As a result, a substance called homogentisic acid builds up in the skin and other body tissues. The acid leaves the body through the urine. The urine turns brownish-black when it mixes with air.
Alkaptonuria is inherited, which means it is passed down from parents to their children. To get this disease, each of your parents must pass you a copy of the faulty HGD gene.
SymptomsUrine in an infant's diaper may darken and can turn almost black after several hours. However, many persons with this condition may not know they have it until mid-adulthood (around age 40), when joint and other problems occur.
Symptoms may include:
- Arthritis (especially of the spine) that gets worse over time
- Darkening of the ear
- Dark spots on the white of the eye (sclera) and cornea
A urine test (urinalysis) is done to test for alkaptonuria. If ferric chloride is added to the urine, it will turn the urine a black color in patients with this condition.
TreatmentSome patients benefit from high-dose vitamin C. This has been shown to decrease the build-up of brown pigment in the cartilage and may slow the development of arthritis.
Expectations (prognosis)The outcome is expected to be good.
ComplicationsPeople with this condition also can get arthritis in adulthood. The build-up of homogentisic acid in the cartilage causes arthritis in about 50% of older adults with alkaptonuria.
- Homogentisic acid also can build up on the heart valves, especially the mitral valve. This can sometimes lead to the need for valve replacement.
- Coronary artery disease may develop earlier in people with alkaptonuria.
- Kidney stonesand prostate stones may be more common in people with alkaptonuria.
Call your health care provider if you notice that your own urine or your child's urine becomes dark brown or black when it is exposed to air.
PreventionThere is no know prevention.
ReferencesChakrapani A, Holme E. Disorders of tyrosine metabolism. In: Fernandes J, Saudubray J-m, van den Berghe G, Walter JH, eds. Inborn Metabolic Diseases: Diagnosis and Treatment. 4th ed. New York, NY: Springer;2006:chap 18.
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∙ 13y ago
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∙ 12y agoAlkaptonuria is a rare condition in which a person's urine turns a dark brownish-black color when exposed to air.
See also: Inborn error of metabolism
Alternative NamesAKU; Alcaptonuria; Homogentisic acid oxidase deficiency; Alcaptonuric ochronosis
Causes, incidence, and risk factorsA defect in the HGD gene causes alkaptonuria.
The gene defect makes the body unable to properly break down certain amino acids (tyrosine and phenylalanine). As a result, a substance called homogentisic acid builds up in the skin and other body tissues. The acid leaves the body through the urine. The urine turns brownish-black when it mixes with air.
Alkaptonuria is inherited, which means it is passed down from parents to their children. To get this disease, each of your parents must pass you a copy of the faulty HGD gene.
SymptomsUrine in an infant's diaper may darken and can turn almost black after several hours. However, many persons with this condition may not know they have it until mid-adulthood (around age 40), when joint and other problems occur.
Symptoms may include:
- Arthritis (especially of the spine) that gets worse over time
- Darkening of the ear
- Dark spots on the white of the eye (sclera) and cornea
A urine test (urinalysis) is done to test for alkaptonuria. If ferric chloride is added to the urine, it will turn the urine a black color in patients with this condition.
TreatmentSome patients benefit from high-dose vitamin C. This has been shown to decrease the build-up of brown pigment in the cartilage and may slow the development of arthritis.
Expectations (prognosis)The outcome is expected to be good.
ComplicationsPeople with this condition also can get arthritis in adulthood. The build-up of homogentisic acid in the cartilage causes arthritis in about 50% of older adults with alkaptonuria.
- Homogentisic acid also can build up on the heart valves, especially the mitral valve. This can sometimes lead to the need for valve replacement.
- Coronary artery disease may develop earlier in people with alkaptonuria.
- Kidney stonesand prostate stones may be more common in people with alkaptonuria.
Call your health care provider if you notice that your own urine or your child's urine becomes dark brown or black when it is exposed to air.
PreventionThere is no know prevention.
ReferencesChakrapani A, Holme E. Disorders of tyrosine metabolism. In: Fernandes J, Saudubray J-m, van den Berghe G, Walter JH, eds. Inborn Metabolic Diseases: Diagnosis and Treatment. 4th ed. New York, NY: Springer;2006:chap 18.
Reviewed ByReview Date: 05/15/2011
Chad Haldeman-Englert, MD, Wake Forest School of Medicine, Department of Pediatrics, Section on Medical Genetics, Winston-Salem, NC. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
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What is the disease caused by a deficiency of Homogentisate oxidase?
Alkaptonuria
What is alcaptonuria?
Alkaptonuria is an inherited condition that causes urine to turn black when exposed to air.
Is alkaptonuria found more frequently in one specific sex?
Black urine disease caused by defected enzymes.Men and women are affected in equal numbers, but it tends to appear earlier in males.
When was muscular dystrophy first recognized as a genetic disorder?
Alkaptonuria was the first identified Genetic disorder noted as following Mendelian Inheritance (by Sir Archibald Garrod in 1902). It is a rare disease: less than one in 250,000 people are affected. Many physicians will never see a patient with Alkaptonuria in their career. It is a recessive disorder, caused by a single gene defect, mapped to Chromosome 3, between regions 3q21-q23. The site of the homogentisate 1,2-dioxygenase (HGD) gene.Alkaptonuria is a genetic disease, meaning that it is passed on by the sufferer's parents. For this to happen both parents must be a carrier of the gene that can cause Alkaptonuria. Because the gene does not always cause Alkaptonuria, people can be carriers without themselves suffering from the disease.If both parents are carriers, the child has a one in four chance of having Alkaptonuria. This happens when the child receives the gene with the disease-causing change from both parents.So even if both parents are carriers, there is still a 75 per cent chance that the child will not have Alkaptonuria. This would be the case if the child receives the gene that doesn't have a disease-causing change from one or both parents.This explains the low incidence of the disease: both parents must be carriers, and both parents must pass on the gene with the disease-causing change. It also explains why one child in a family may have Alkaptonuria but their siblings may not.What Alkaptonuria doesPeople with Alkaptonuria do not have enough of an enzyme called homogentisic acid oxidase. The body uses this enzyme to break down a substance called homogentisic acid. Because normal amounts of this enzyme are missing,homogentisic acid is not used and builds up in the body. Some is eliminated in the urine, but the rest is deposited in body tissues, where it accumulates at 2,000 times the normal rate.This accumulation of homogentisic acid causes ochronosis, a blue-black discoloration of connective tissue including bone, cartilage, and skin caused by deposits of ochre-colored pigment. And because homogentisic acid is toxic, this build-up in the body tissues eventually leads to multiple and chronic health problems for Alkaptonuria sufferers.Diagnosis and symptomsBabies born with Alkaptonuria do not suffer any immediate ill effects. However, because of the presence in their urine of homogentisic acid, which turns a dark colour after several hours' exposure to air, parents may notice dark staining of the baby's nappies or diapers. If proper tests are then carried out, this can lead to diagnosis of the disease.Many sufferers, however, are not diagnosed with Alkaptonuria until symptoms appear later in life, after years of accumulation of homogentisic acid in their body tissues. The onset of clinical joint disease may differ from an age of six years to an age of 60 years. Generally, there is increasing joint pain and limited and painful use of the large weight-bearing joints: knees, hips, spine and shoulders.The main symptoms and some of the health problems caused by Alkaptonuria and ochronosis are described below.Skeletal (bones and cartilage)The knees, shoulders, and hips are most affected. Deposits of pigment cause cartilage to become brittle and eventually to fragment (break apart). Arthropathy (diseased joints characterised by swelling and enlarged bones) is common.Patients suffer intense joint pain and decreased mobility. Many will have surgery to replace affected joints. Sometimes patients end up wheelchair-bound.In general, people start complaining of back pain in their 20s and 30s, and knee pain in their 40s. However, the onset of symptoms depends on the individual and can vary greatly. Hip and shoulder pain often occurs later, but usually by the age of 50. Many people have at least one joint replaced by age 55.Cardiovascular (heart and blood vessels)Heart problems often start after age 50. These include calcification of the coronary arteries (the vessels that feed the heart). The aortic and mitral heart valves -- which separate chambers of the heart -- are most affected. The build-up of homogentisic acid can cause valves to calcify or harden, leading to narrowing of the valve causing problems with blood flow. Pigment deposits also can lead to the formation of atherosclerotic plaques (hard spots in arteries) containing cholesterol and fat.Genitourinary (genital and urinary systems and organs)In men, the prostate is most commonly affected. Pigment deposits can form stones in the prostate.Respiratory (organs and structures involved in breathing)Heavy pigment deposits are common in the cartilage of the larynx (voice box), the trachea (windpipe), and the bronchi (air passages to the lungs).Ocular (eyes)Vision is not usually affected, but pigmentation in the white part of the eye is evident in most patients by their early 40s.Cutaneous (skin)Again, the age at which this becomes noticeable varies according to the individual. Effects are most noticeable in areas where the body is exposed to the sun and where sweat glands are located. Skin takes on a blue-black speckled discoloration. Sweat can actually stain clothes brown.Pigmentation of the skin is more visible in some patients than others. It is often first seen in the ear lobe. It can also be seen in the bridge of the nose, cheeks, hands, and skin overlying tendons.Other body systemsThe teeth, central nervous system (brain and spinal cord), and endocrine organs (which make hormones) also may be affected.Description taken from The Alkaptonuria website -http://www.alkaptonuria.info/380158
What test would indicate a problem with carbohydrate metabolism?
Doctors can order either a blood or urine test to determine if a person has a problem with their carbohydrate metabolism. While both tests can detect problems with metabolism, results have shown blood testing to be more accurate.
Is alkaptonuria caused by a recessive or dominant allele?
Phenylketonuria is an autosomal recessive genetic disorder. The enzyme phenylalanine hydroxylase is necessary to metabolize phenylalanie, but when this enzyme doesnt work, phenylaline accumulates and is detected in the urine. The disease is detected during pregnancy, and if treated right away the newborn can develop normally. However, if left untreated, the brain will not develop properly.
What does grey colored urine mean?
if the end is dark you may have some internal bleeding This means you have optermosefaciotious dieases. If you have had bloating, constapation, diarrea explosions, and an unnormal feeling while eating ice cream, consult with your doctor immemadiatly.
What are some abnormal urinalysis results and describe them?
These are all screening test, but not confirmation test. Red, cloudy urine means hematuria (blood in the urine) Red, clear urine means hemaglobinuria (hemaglobin in the urine. Dark reddish brown cola-colored urine means Myoglobinuria (myoglobin in the urine) Beer-brown-colored urine means indicative of bilirubin Dark red like port wine-colored urine means porphyrins (iron pigment). Very turbid urine means pyuria (Abnormal numbers of white blood cells in the urine) Orange Urine means the patient consume a lot of beta-carotene. Black to Dark brown urine means Alkaptonuria (melanin or homogentisic acid in the urine) Huge amount of urine means polyuria and may have type I/II diabetes High bilirubin levels in urine means hepatitis/jaundice High urobilinogen level in urine means excessive destruction of Red blood cells or patient have infectious mononucleosis. Low / No Urobilinogen and High Bilirubin in urine with high levels of bilirubin in the blood means Obstruction of Bile ducts/Obstructive jaundice Urine positive for Ketones means diabetic ketoacidosis, the patient is diabetic or having a crash diet. High glucose level in urine means lack of control of the diabetes High glucose level and normal blood sugar level means lowered renal threshold. Marked High Protein level in the urine means Nephrotic syndrome, Renal vein thrombosis, Amyloid disease, Lupus erythematosus. (4 gms/day) High protein level and heated at 100 C becomes normal/low protein level means multiple myeloma/macroglobulinemia. There are more informations if you bought the urinalysis book.
What are the disorders of Phenylalanine or Tyrosine Metabolism in Humans?
Phenylalanine Metabolism in HumansThe metabolism of the aromatic amino acids-phenylalanine and tyrosine in man provides a best example of a gene-controlled, enzyme catalyzed biochemical reaction. In man, phenylalanine is an essential amino acid which must be supplied in the dietary proteins. Once in the body, phenylalanine may follow any of three paths. It may be (1) incorporated into cellular proteins, (2) converted to phenylpyruvic acid, or (3) converted to tyrosine. The conversion of phenylalanine into tyrosine takes place in the presence of phenylalanine hydroxylase enzyme, in the liver cells. Tyrosine is converted in turn to 3-4-dihydroxy phenylalanine (nick-named DOPA) by another enzyme and DOPA serves as a precursor for the hormones adrenaline and noradrenaline and for the black pigment, melanin.Tyrosine itself serves as a precursor of the hormones thyroxine and triiodothyronine. Excess tyrosine is degraded to carbon dioxide and water by a series of steps which involves the formation of p-hydroxyphenyl pyruvate, 2-5 dihydroxy phenyl pyruvate, homogentisic acid, maleylacetoacetic acid, fumaryl acetoacetic acid and fumaric and acetoacetic acid. Excess phenylalanine is degraded by a series of steps to compounds which include phenylpyruvic acid and phenyl lactic acid.Genetic disorders of the phenylalanine metabolism and resulted diseases-Five rare diseases in man result from improper functioning of five enzyme systems (i.e., metabolic blocks) involved in the metabolism of phenylalanine, tyrosine and their derivatives. All of these diseases have been found to be due to mutant, autosomal recessive genes in homozygous conditions. These diseases are following:1.Phenylketonuria-Persons with genotype pp fail to produce enzyme phenylalanine hydroxylase (parahydroxylase) with the result that phenylalanine fails to convert into tyrosine and consequently, the concentration of phenylalanine rises in the blood plasma, cerebrospinal fluid and urine. The urine of phenylketonuric (PKUJ patient contains (in addition to phenylalanine) elevated amounts of phenylpyruvic acid, phenyl lactic acid and other derivatives of phenylalanine. PKU patients have light pigmentation and are physically and mentally retarded. The feeble mindedness in PKU patients is thought to -be due to an impairment of the brain tissues by the phenylpyruvic acid in the cerebro-spinal fluid.2. Alkaptonuria- The persons with genotype hh fail to produce the enzyme homogentisic acid oxidase which catalyzes the oxidation of homogentisic acid. Therefore, in them, normal oxidation of homogentisic acid into water and carbon dioxide does not occur and large amounts of homogentisic acid are excreted in the urine, which turn black upon exposure to the air. Moreover, the homogentisic acid accumulate in the body and become attached to the collagen of cartilage and other connective tissues, due to which, the ear and sclerae are stained black. Persons with such phenotypic abnormalities are said to have alkaptonuria disease.3. Tyrosinosis-The recessive gene, t in its homozygous condition, blocks the conversion of p-hydroxyphenylpyruvate into 2, S-dihydroxyphenyl pyruvate. This leads to the accumulation of tyrosine, excesses of which are excreted via the urine. This condition is called tyrosinosis. It is reported in only one human and cause no harmful effect.4. Goitrous cretinism-The persons with cc genotype fail to produce the enzyme which is required for the conversion of tyrosine into thyroxine and triiodothyronine hormones in their thyroid glands. This condition is called goitrous cretinism which is accompanied by a considerable degree of physical and mental retardation and hypertrophy of thyroid gland.5. Albinism- The persons with recessive AA genotype lack in the tyrosinase enzyme system which is required for the conversion of 3, 4-dihydroxyphenyl alanine (DOPA) into melanin pigment inside the melanocytes. In an albino patient melanocytes are present in normal numbers in their skin, hairs, iris, etc., but lack in melanin pigment.
What rhymes with hematuria?
End rhymes for "hematuria": 1. acetonuria 2. acholuria 3. achromaturia 4. aciduria 5. adiposuria 6. albiduria 7. albinuria 8. albuminuria 9. alcaptonuria 10. alkalinuria 11. alkaluria 12. alkaptonuria 13. allantoinuria 14. alloxuria 15. ameburia 16. aminoaciduria 17. aminuria 18. ammoniuria 19. amylasuria 20. amylosuria 21. amyluria 22. anuria 23. archosauria 24. aspartylglycosaminuria 25. azoturia 26. bacilluria 27. bacteriuria 28. baruria 29. beeturia 30. bilirubinuria 31. biliuria 32. blennuria 33. bradyuria 34. calcariuria 35. calciuria 36. carbohydraturia 37. carboluria 38. centuria 39. chloriduria 40. chloruria 41. cholesteroluria 42. choleuria 43. choluria 44. chromaturia 45. chyluria 46. citrullinuria 47. creatinuria 48. crystalluria 49. curia 50. cylindruria 51. cystathioninuria 52. cystinuria 53. cyturia 54. dextrinuria 55. diastasuria 56. dinosauria 57. dysuria 58. enaliosauria 59. eosinophiluria 60. erythruria 61. etruria 62. fibrinuria 63. fructosuria 64. galactosuria 65. globulinuria 66. glucosuria 67. glutathionuria 68. glycosuria 69. haematocyturia 70. haematuria 71. haemoglobinuria 72. halisauria 73. hematocyturia 74. hematuria 75. hemoglobinuria 76. histidinuria 77. histonuria 78. holothuria 79. homaluria 80. homocitrullinuria 81. homocystinuria 82. hyalinuria 83. hydrothionuria 84. hypercalcinuria 85. hypercalciuria 86. hyperglycinuria 87. hyperglycosuria 88. hyperketonuria 89. hyperlysinuria 90. hyperoxaluria 91. hyperphosphaturia 92. hypersthenuria 93. hyperuricuria 94. hypoaldosteronuria 95. hypoazoturia 96. hypochloruria 97. hypocitraturia 98. hypophosphaturia 99. hyposthenuria 100. hypouricuria from: rhymezone.com
