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| '''For patient information, click [[Galactosemia (patient information)|here]]
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| {{Infobox_Disease | | {{Galactosemia}} |
| | Name = {{PAGENAME}}
| | {{CMG}} ; '''Associate Editor-In-Chief:''' {{CZ}} {{MUT}} |
| | Image = Galactose Haworth.png
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| | Caption = [[Galactose]]
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| | DiseasesDB =
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| | DiseasesDB_mult =
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| | ICD10 = {{ICD10|E|74|2|e|70}}
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| | ICD9 = {{ICD9|271.1}}
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| | MeshID = D005693
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| {{SI}} | |
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| ==Overview== | | ==[[Galactosemia overview|Overview]]== |
| '''Galactosemia''' is a rare genetic metabolic disorder which affects an individual's ability to properly metabolize the sugar [[galactose]]. In individuals with galactosemia, the enzymes needed for further metabolism of galactose are severely diminished or missing entirely, leading to toxic levels of galactose to build up in the blood, resulting in [[hepatomegaly]] (an enlarged [[liver]]), [[renal failure]], [[cataract]]s, and [[brain damage]].
| | ==[[Galactosemia historical perspective|Historical Perspective]]== |
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| Goppert first described the disease in 1917,<ref>Goppert F. ''Galaktosurie nach Milchzuckergabe bei angeborenem, familiaerem chronischem Leberleiden.'' Klin Wschr 1917;54:473-477.</ref> with its cause as a defect in galactose metabolism being identified by a group led by [[Herman Kalckar]] in 1956.<ref>{{cite journal |author=Isselbacher KJ, Anderson EP, Kurahashi K, Kalckar HM |title=Congenital galactosemia, a single enzymatic block in galactose metabolism |journal=Science |volume=13 |issue=123 |pages=635-6 |year=1956 |pmid=13311516}}</ref>
| | ==[[Galactosemia classification|Classification]]== |
| | ==[[Galactosemia pathophysiology|Pathophysiology]]== |
| | ==[[Galactosemia causes|Causes]]== |
| | ==[[Galactosemia differential diagnosis|Differentiating Galactosemia from other Diseases]]== |
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| Its incidence is about 1 per 47,000 births (classic type). It is much rarer in Japan and much more common in Italy, specifically the traveler region.
| | ==[[Galactosemia epidemiology and demographics|Epidemiology and Demographics]]== |
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| ==Cause== | | ==[[Galactosemia risk factors|Risk Factors]]== |
| [[Lactose]] in food (such as dairy products) is broken down by the body into [[glucose]] and galactose. | | ==[[Galactosemia screening|Screening]] == |
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| <gallery>
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| Image:Lactose(lac).png |[[Lactose]]
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| Image:Glucose wpmp.png|[[Glucose]]
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| </gallery>
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| In individuals with galactosemia, the enzymes needed for further metabolism of galactose are severely diminished or missing entirely, leading to toxic levels of galactose to build up in the blood, resulting in [[hepatomegaly]] (an enlarged [[liver]]), [[renal failure]], [[cataract]]s, and [[brain damage]]. Without treatment, mortality in infants with galactosemia is about 75%.
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| Shown below is a diagram depicting galactose metabolism and the different enzymes involved in it.
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| [[File:Galactose_metabolism.png]]
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| ==Types== | |
| Galactose is converted into glucose by the action of three enzymes, known as the Leloir pathway. Accordingly, there are 3 known types of Galactosemia; type 1, 2 and 3:
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| {| class="wikitable"
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| | '''Type''' ||'''[[Diseases Database]]''' || '''[[OMIM]]''' || '''Gene ''' || '''[[Locus (genetics)|Locus]]''' || '''Enzyme''' || '''Name'''
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| |Type 1|| {{DiseasesDB2|5056}} || {{OMIM2|230400}} || {{Gene|GALT}} || 9p13|| [[galactose-1-phosphate uridyl transferase]] || [[classic galactosemia]]
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| |Type 2|| {{DiseasesDB2|29829}} ||{{OMIM2|230200}} || {{Gene|GALK1}} || 17q24|| [[galactokinase]] || [[galactokinase deficiency]]
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| |Type 3||{{DiseasesDB2|29842}} || {{OMIM2|230350}}|| {{Gene|GALE}} || 1p36-p35 || [[UDP galactose epimerase]] || galactose epimerase deficiency, UDP-Galactose-4-epimerase deficiency
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| |}
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| The order of these three types is not the same as the order that the enzymes are encountered by galactose on its metabolic path (which is closer to GALK, GALT, and then GALE, though many variations can occur.)
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| | ==[[Galactosemia natural history, complications and prognosis|Natural History, Complications and Prognosis]]== |
| ==Diagnosis== | | ==Diagnosis== |
| Infants are now routinely screened for galactosemia in the United States, and the diagnosis is made while the person is still an infant.
| | [[Galactosemia history and symptoms|History and Symptoms]] | [[Galactosemia physical examination|Physical Examination]] | [[Galactosemia laboratory findings|Laboratory Findings]] | [[Galactosemia CT|CT]] | [[Galactosemia MRI|MRI]] | [[Galactosemia echocardiography or ultrasound|Ultrasound ]] | [[Galactosemia other imaging findings|Other Imaging Findings]] | [[Galactosemia other diagnostic studies|Other Diagnostic Studies]] |
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| ==Treatment== | | ==Treatment== |
| The only treatment for classic galactosemia is eliminating lactose and galactose from the diet. Even with an early diagnosis and a restricted diet, however, some individuals with galactosemia experience long-term complications such as speech difficulties, [[learning disabilities]], neurological impairment (e.g. tremors, etc), and in girls, ovarian failure. These complications are treated if they appear in a manner similar to the way they would be treated in a non-galactosemic. Such complications have not been associated with Duarte galactosemia, and many individuals with Duarte galactosemia do not need to restrict their diet at all. Infants with classic galactosemia cannot be breast-fed due to lactose in human breast milk and are usually fed a soy-based formula.<ref>http://www.cdc.gov/breastfeeding/disease/contraindicators.htm</ref>
| | [[Galactosemia medical therapy|Medical Therapy]] | [[Galactosemia surgery|Surgery]] | [[Galactosemia primary prevention|Primary Prevention]] | [[Galactosemia secondary prevention|Secondary Prevention]] | [[Galactosemia cost-effectiveness of therapy|Cost-Effectiveness of Therapy]] | [[Galactosemia future or investigational therapies|Future or Investigational Therapies]] |
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| Galactosemia is sometimes confused with [[lactose intolerance]], but galactosemia is a more serious condition. Lactose intolerant individuals have an acquired or inherited shortage of the enzyme [[lactase]], and experience abdominal pains after ingesting dairy products, but no long-term effects. In contrast, a galactosemic individual who consumes galactose can cause permanent damage to their bodies. | |
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| Long term complication of galactosemia includes:
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| *Speech deficits
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| *[[Ataxia]]
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| *[[Dysmetria]]
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| *[[osteopenia|Diminished bone density]]
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| *[[Premature ovarian failure]]
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| *[[Cataract]]
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| For a thorough scientific overview of galactosemia, one can consult chapter 72 of OMMBID<ref>
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| [[Charles Scriver]], Beaudet, A.L., Valle, D., Sly, W.S., Vogelstein, B., Childs, B., Kinzler, K.W. (2006). [http://www.ommbid.com The Online Metabolic and Molecular Bases of Inherited Disease]. New York: McGraw-Hill. -
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| Free summaries of 255 chapters, full text through many universities and organizations. Also, the [http://books.mcgraw-hill.com/medical/ommbid/blog/ OMMBID blog].
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| </ref>. For more online resources and references, see [[inborn error of metabolism]]. <br />
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| ==References==
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| {{reflist|2}}
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| {{Endocrine, nutritional and metabolic pathology}}
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| [[de:Galaktosämie]]
| | ==Case Studies== |
| [[es:Galactosemia]]
| | [[Galactosemia case study one|Case #1]] |
| [[fr:Galactosémie]]
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| [[nl:Galactosemie]]
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| [[ja:ガラクトース血症]]
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| [[pl:Galaktozemia]]
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| [[pt:Galactosemia]] | |
| [[ru:Галактоземия]]
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| [[sr:галактоземија]]
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| [[Category:Mature chapter]]
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| [[Category:Inborn errors of metabolism]]
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| [[Category:Genetic disorders]]
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| [[Category:Metabolic disorders]]
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| [[Category:Genetic Disease]]
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