Dubin-Johnson and Rotor Syndromes
On this page
Direct answer
Two eponyms, one clinical picture — isolated conjugated jaundice in an otherwise healthy person, with normal alkaline phosphatase, transaminases and albumin, autosomal recessive inheritance, and a normal life expectancy. Dubin-Johnson is a canalicular export defect (MRP2/ABCC2) with a characteristically black liver; Rotor is a hepatic uptake-and-storage defect (OATP1B1/1B3) with a histologically normal liver. The urinary coproporphyrin pattern separates them: total normal with isomer I dominance in Dubin-Johnson, total markedly raised in Rotor.
What you must remember
- Shared features: benign chronic conjugated hyperbilirubinaemia (bilirubin usually 2–5 mg/dL), otherwise normal liver panel, autosomal recessive, often unmasked or worsened by pregnancy or oral contraceptives.
- Dubin-Johnson: defect of the canalicular multidrug-resistance-associated protein 2 (MRP2, ABCC2 gene) — bilirubin glucuronides cannot leave the hepatocyte.
- The black liver: Dubin-Johnson biopsy shows dark brown-black pigment (epinephrine-derived melanin-like pigment) in hepatocytes — diagnostic and a viva favourite.
- Dubin-Johnson cholecystography: oral cholecystographic media fail to visualise the gallbladder — the classic historical test.
- Rotor: defect of the basolateral uptake transporters OATP1B1 and OATP1B3 (SLCO1B1, SLCO1B3); liver histology normal; no pigment.
- Coproporphyrin discriminator: Dubin-Johnson — total urinary coproporphyrin normal, with over 80% as isomer I (normal about 25%); Rotor — total urinary coproporphyrin markedly raised (around fivefold), with isomer I about 65%.
- Management is reassurance: no drug, no diet, no biopsy needed beyond diagnosis; counsel patients before pregnancy and about the OCP effect.
- Exam pairing logic: these two belong to the conjugated family while Gilbert and Crigler-Najjar occupy the unconjugated side of the same inherited-jobs table.
The coproporphyrin fractions decide it
Run the differentiation on one vignette: a 24-year-old medical student, jaundiced since a fever last year, with bilirubin 3.2 mg/dL — predominantly direct — and completely normal ALP, AST, albumin and ultrasound. Two suspects, one test. If urinary coproporphyrin comes back with a normal total but an isomer I fraction of 85%, the transport failure is at the canalicular membrane — the glucuronide is made but cannot leave — and that is Dubin-Johnson; a liver biopsy, if someone insists, would return a startlingly black specimen from pigment that is neither bile nor iron. If instead the total urinary coproporphyrin is roughly five times normal with only a modest isomer I shift, the fault lies at the sinusoidal membrane — the OATP uptake/storage defect of Rotor — and the liver looks histologically ordinary. Neither patient needs treatment: the diagnosis's purpose is to stop the medical system from chasing obstruction, hepatitis or haemolysis. Note the examinable asymmetry in the two membranes' failures: in Dubin-Johnson the hepatocyte is full of pigment (hence the colour), while in Rotor bilirubin simply shuttles poorly between blood and liver — which is also why the historical oral cholecystogram fails only in Dubin-Johnson.
Do not chase disease when the LFTs are quiet
The perspective the examiner builds stems around: a young adult with isolated direct hyperbilirubinaemia and a normal liver panel is one of medicine's few situations where the correct next action is near-nothing — after the coproporphyrin (or genetic) confirmation. Candidates who reflexively order MRCP, hepatitides screens and serial biopsies demonstrate the reflex the question is designed to punish. The second trap is inverting the two syndromes' fingerprints: black liver and failed gallbladder visualisation belong to Dubin-Johnson; the fivefold coproporphyrin rise belongs to Rotor — rehearse the pairing until it is automatic. Third, remember the hormonal unmasking: pregnancy and oral contraceptives deepen jaundice in both, a detail that turns up in obstetric-medicine stems. And finally the inheritance: both are autosomal recessive, which is why the "jaundiced since childhood, everything else normal" sibling pair is a stem-clue worth circling.
Frequently asked questions
What is the transport defect in Dubin-Johnson syndrome?
Loss of the canalicular exporter MRP2 (ABCC2), so bilirubin glucuronides cannot leave the hepatocyte — causing conjugated hyperbilirubinaemia with a pigmented black liver.
How do urinary coproporphyrins separate the two syndromes?
Dubin-Johnson shows a normal total with isomer I above 80%; Rotor shows a markedly raised total (around fivefold) with isomer I about 65%.
What does the liver biopsy show in each?
Dubin-Johnson — dark melanin-like pigment giving the classic black liver; Rotor — histologically normal liver.
Why do pregnancy and oral contraceptives worsen the jaundice?
Both deepen the subclinical transport defect, unmasking or intensifying hyperbilirubinaemia — a classic clinical clue in these benign syndromes.
What treatment do these syndromes need?
None — reassurance, counselling on benignity and on OCP/pregnancy effects; no drug or dietary therapy alters the defect.