Defective hepatic anion transport in variegate porphyria

A 29-yr-old man with neurological symptoms that included tremor, dysarthria, and loss of consciousness was diagnosed as having variegate porphyria, because of increased urinary excretion of delta-aminolevulinic acid, porphobilinogen, uroporphyrin, and coproporphyrin, and increased fecal uro-, copro-, and protoporphyrins. He showed marked retention of indocyanine green (R15 min: 53%-78%) and bromosulfophthalein (R45 min: 24%-10%) as well. The kinetic analysis revealed that both hepatic uptake and hepatic excretion were decreased for both dyes. Results of other liver function tests were unremarkable except for intermittent hyperbilirubinemia (0.7-3.3 mg/100 ml), of which the ratio of conjugated and unconjugated fraction was between 0.7 and 1.2. Binding of serum protein and indocyanine green or bromosulfophthalein was normal. An angiographic and scintigraphic study of the liver was normal. A minimal deposition of hemosiderin pigment was found in liver biopsy specimen without other abnormalities. Deposition of porphyrin was not present in the liver. Plasma exchange and erythrocytapheresis did not show any beneficial effects on the clinical and laboratory abnormalities of the patient. A possible relationship between variegate porphyria and defective hepatic anion transport is discussed.