[Byler's disease. Ultrastructural study. Apropos of a case in an infant].

A case of familial cholestasis with cirrhosis is described in a 8 months old boy, presenting with hepatosplenomegaly, portal hypertension, dramatic pruritus, and fluctuating icterus of early post-natal onset. Biological data include positive hepatocyte retention test, with mild hepatocyte cytolysis, without patent hepatocyte insufficiency. The discrepancy between the clinical symptoms and a slight elevation of bilirubin partially conjugated, the absence of elevated blood cholesterol, the absence of evidence of antigen or antibody of virus A or B, the marked elevation of blood biliary acid lead to the suspicion of Byler disease. A liver biopsy with ultrastructural study shows a thickening of the ectoplasm, and the presence of microfilament material in the lumen of partially broken villi. Comparisons are made with the 4 other cases of Byler disease with E.M. study documented in the literature.