Dubin-Johnson syndrome
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2008-05-22T19:16:12Z
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{{refimprove|date=December 2007}}
{{Infobox_Disease |
Name = {{PAGENAME}} |
Image = Bilirubin.svg |
Caption = [[Bilirubin]] |
DiseasesDB = 3982 |
ICD10 = {{ICD10|E|80|6|e|70}} |
ICD9 = {{ICD9|277.4}} |
ICDO = |
OMIM = 237500 |
MedlinePlus = |
eMedicineSubj = med |
eMedicineTopic = 588 |
MeshID = D007566 |
}}
'''Dubin-Johnson syndrome''' is an [[autosomal recessive]] disorder which causes an increase of conjugated [[bilirubin]] without elevation of [[liver]] [[enzymes]] ([[Alanine transaminase|ALT]], [[aspartate transaminase|AST]]). This condition is associated with a defect in the ability of hepatocytes to secrete conjugated [[bilirubin]] into the bile. It is usually diagnosed in early infancy.
==Diagnosis==
There is plenty of canalicular multi-drug resistant protein which causes bilirubin transfer to [[bile canaliculi]]. An isoform of this protein is localized to the lateral hepatocyte membrane, allowing transport of [[glucuronide]] and [[glutathione]] conjugates back into the blood.
Analysis of urine porphyrins show a normal level of coproporphyrin but the I isomer accounts for 80% of the total (normally 25%)
Liver will present with dark pink or black appearance due to [[pigment]] accumulation.
The conjugated hyperbilirubinemia is a result of defective endogenous and exogenous transfer of anionic conjugates from hepatocytes into the bile.<ref name="Carter">Suzanne M Carter, MS. eMedicine: Dubin-Johnson Syndrome. January 9, 2007. http://www.emedicine.com/ped/topic621.htm</ref> Pigment deposition in lysosomes causes the liver to turn black.
A hallmark of DJS is the unusual ratio between the byproducts of heme biosynthesis.
Unaffected subjects have a coproporphyrin III to coproporphyrin I ratio of approximately 3-4:1.
In patients with DJS, this ratio is inverted with coproporphyrin III being 3-4x higher then coproporphyrin I.
==Genetics==
[[Image:autorecessive.jpg|thumb|right|Dubin-Johnson syndrome has an autosomal recessive pattern of inheritance.]]
DJS has a defect in the multispecific anion transporter ([[cMOAT]]) gene (ABC transporter superfamily).
Likely a loss of function mutation, since the mutation affects the cytoplasmic / binding domain.
==Prognosis==
Prognosis is good, and treatment of this syndrome is usually unnecessary. Most patients are asymptomatic and have normal life spans.<ref name="Carter" /> Some neonates will present with cholestasis.<ref name="Carter" />
Oral contraceptive and pregnancy may lead to overt jaundice and icterus (yellowing of the eyes)
==References==
{{reflist}}
==See also==
*[[Jaundice]]
*[[Gilbert syndrome]]
*[[Crigler-Najjar syndrome]]
*[[Rotor syndrome]]
{{Heme metabolism disorders}}
[[Category:Gastroenterology]]
[[Category:Hepatology]]
[[Category:Syndromes]]
[[Category:Genetic disorders]]
[[Category:Autosomal recessive disorders]]
{{genetic-disorder-stub}}
[[de:Dubin-Johnson-Syndrom]]
[[es:Síndrome de Dubin-Johnson]]
[[pl:Zespół Dubina-Johnsona]]