A 28-year-old pregnant woman is concerned about the yellowing of her eyes and skin and goes to see her obstetrician. Blood work shows mildly elevated levels of direct-reacting bilirubin. Analysis of her urine shows significant amounts of coproporphyrin I. Which of the following disorders most likely explains the signs and symptoms in this patient?

Question

Quizplus · Accepted Answer

Dubin-Johnson syndrome is characterized by conjugated hyperbilirubinemia and the presence of coproporphyrin I in the urine, which matches the patient's symptoms and lab findings.  Dubin-Johnson syndrome is inherited as an autosomal recessive disorder characterized by mild, predominantly conjugated hyperbilirubinemia. The syndrome results from mutations in the bile canalicular multispecific organic anion transporter (CMOAT). The CMOAT gene is also referred to as the ATP-binding cassette, subfamily C, member 2 gene (ABCC2), and the multidrug resistance-associated protein 2 gene (MRP2). This transporter is involved in the excretion of many nonbile organic anions by an ATP-requiring process. The defect-causing Dubin-Johnson syndrome leads to an abnormality in porphyrin metabolism such that more than 80% of the urinary compound from this pathway is coproporphyrin I, whereas in a normal individual it is usually less than 35%. Jaundice is usually the only physical symptom detected in this disease. Women may exhibit overt symptoms for the first time when taking oral contraceptives or when pregnant

A 28-Year-Old Pregnant Woman Is Concerned About the Yellowing of Her