During the past decade increasing attention has been paid to a group of congenital or familial diseases of bilirubin metabolism, prompted largely by the hope that these diseases might provide some clues to the mysteries of bilirubin uptake, conjugation, and excretion by the liver cell. Among these diseases are two conditions characterized by jaundice and an increase in serum levels of both the conjugated and unconjugated fractions of bilirubin. These are Rotor's syndrome1,2 and chronic idiopathic jaundice.3-5 Some workers have suggested that these two conditions are close relatives, or even variants of a single disease. Others have scrapped the original criteria set down for these entities and have instituted radical changes in established terminology. Because such premature breaches in nomenclature may lead to obfuscation, I believe it desirable to reexamine the current status of these conditions.
In our present state of knowledge, the major differences between these two