- Dubin-Johnson syndrome
Infobox_Disease
Name = PAGENAME
Caption =Bilirubin
DiseasesDB = 3982
ICD10 = ICD10|E|80|6|e|70
ICD9 = ICD9|277.4
ICDO =
OMIM = 237500
MedlinePlus =
eMedicineSubj = med
eMedicineTopic = 588
MeshID = D007566Dubin-Johnson syndrome is an
autosomal recessive disorder which causes an increase of conjugatedbilirubin without elevation ofliver enzymes (ALT, AST). This condition is associated with a defect in the ability of hepatocytes to secrete conjugatedbilirubin into the bile. It is usually asymptomatic but may be diagnosed in early infancy based on laboratory tests.Pathophysiology
The conjugated hyperbilirubinemia is a result of defective endogenous and exogenous transfer of anionic conjugates from hepatocytes into the bile.Suzanne M Carter, MS EMedicine|ped|621|Dubin-Johnson Syndrome] Pigment deposition in lysosomes causes the liver to turn black.
Diagnosis
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 I being 3-4x higher than coproporphyrin III. Analysis of urine
porphyrin s show a normal level of coproporphyrin but the I isomer accounts for 80% of the total (normally 25%). In post-mortemautopsy , the liver will have a dark pink or black appearance due topigment accumulation.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 apical hepatocyte membrane, allowing transport ofglucuronide andglutathione conjugates back into the blood.Genetics
DJS is due to a defect in the multispecific anion transporter (
cMOAT ) gene (ABC transporter superfamily). It is an autosomal recessive disease and is likely due to 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. Some neonates will present with cholestasis.
Oral contraceptive s andpregnancy may lead to overt jaundice and icterus (yellowing of the eyes).References
ee also
*RareDiseases|6289|Dubin-Johnson syndrome
*Jaundice
*Gilbert syndrome
*Crigler-Najjar syndrome
*Rotor syndrome
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