[Gilbert's jaundice. Current clinico-nosographic physiopathological and therapeutical aspects. I. Recent findings in Gilbert's syndrome].

Gilbert's icterus is a term used to cover certain forms of free bilirubin hyperbilirubinaemia which occur without any clear signs of hyperhaemolysis and are thus based on a fundamental defect in bilirubin liver cell clearance. Speculatively, this defect may be considered as being located at the level of any one of the steps along the metabolic route of the pigment, between the vascular pole of the liver cell and the microsomes. The incidence of these forms is calculated at about 4-6% of the population, while study of its familial distribution would suggest its inclusion among genetically conditioned metabolic disturbances. Investigations of various groups of patients suggest heredity of poorly penetrating, incomplete expressivity dominant autosomic type. As for pathogenesis, analysis of the formation of glycuronide bilirubin on the part of liver microsomes has shown a frequent reduction in glycuronyltransferase activity in patients with Gilbert's icterus; on the other hand, separation of the two carrier proteins y and z, and kinetic studies with free radiobilirubin, suggest that in certain of these subjects there is an alteration in the liver cell's capacity to take up and hold bilirubin removed from the blood. On the basis of such data, Gilbert's icteruses have been traditionally subdivided into two types: the first, with slight bilirubinaemia, due to an uptaking defect, the second, with higher bilirubin, due to a reduction in glycuronide conjugation. From the morphological viewpoint, the optical microscope does not reveal any outstanding elements in the livers of Gilbert patients; some workers using the electronic microscope have insisted on the not infrequent presence of damage to the vascular pole of the liver cell, which would fall in with the hypothesis of a membrane pathology as the underlying factor in one type of Gilbert's icterus. Numerous granules with lysosome characteristics have also been seen at the biliary pole of the liver cell. Whether these are the cause of the disease or, as would appear more likely, they are only an epiphenomenon secondary to the accumulation of a non-metabolized product of the liver, is still under discussion. Theoretically, therefore, two groups can be distinguished for free bilirubin icteruses of hepatic pathogenesis and thus not only for Gilbert's icterus; those due to a membrane or y and z carrier pathology, and those with microsome pathology due to partial glycuronyltransferase deficiency. The most recent tendency is thus to unify under the common label of a glycuronyltransferase deficiency the type II of Gilbert's icterus and the Crigler-Najjar disease, even though gene transmission modalities differ. Some workers thus suggest two types of Crigler-Najjar disease: type I, the classical type, due to absolute glycuronyltransferase deficiency and type II due to a relative deficiency, taking in the II form of Gilbert's icterus...