Genetic cholestasis: classification according to the cellular defect.

Advances in molecular biology achieved during the last years have allowed us to know the genes involved in biliary secretion and the mutations capable of generating cholestasis. The mechanisms involved in forming bile and its circulation have been clarified. According to the biology of biliary secretion, we classify the genetic causes of cholestasis as follows: 1) transport abnormalities in canalicular or basolateral membranes, 2) alterations in intracellular vesicle transit, 3) increased paracellular permeability, 4) mutations in nuclear receptors, 5) cholangiopathies, and 6) hepatocellular diseases, due to disturbance of the function of intracellular organelles or errors of metabolism. This physiopathological classification of chronic cholestasis in childhood will facilitate pediatricians' diagnostic guidance and timely specialized referrals, as patients should receive early and appropriate treatment for its complications.