Liver ultrastructure in Gilbert's syndrome.

Electron microscopy of hepatic tissue obtained by percutaneous needle biopsy from nine patients with Gilbert's syndrome has revealed in every case gross hypertrophy of hepatocyte agranular endoplasmic reticulum but no other important abnormality. While this may have relevance to impairment of microsomal enzyme activity controlling bilirubin conjugation within liver cells, the serum bilirubin levels in all nine patients were below that normally associated with demonstrable UDP-glucuronyl transferase deficiency. Gross hypertrophy of agranular endoplasmic reticulum may be, therefore, a constant feature of this form of Gilbert's syndrome and may have some diagnostic value in the investigation of unconjugated hyperbilirubinaemia.