Cystic fibrosis liver disease in children - A review of our current understanding.

Cystic fibrosis is the second most common genetic disease in infancy. It is the result of a mutated channel protein, the CFTR, which secretes chloride ions, fluidifying secretions. Recent improvements in the treatment have increased life expectancy in these patients. Nevertheless, liver involvement remains the third cause of death. Unfortunately, our understating of the physiopathology is still deficient. Biliary obstruction secondary to the presence of thick secretions is considered to lead to cirrhosis. However, treatment with ursodeoxycolic acid has not changed the natural history. Furthermore, the presence of portal hypertension in the absence of cirrhosis cannot be explained. Recently, the role of CFTR as modulator of immune tolerance has been proposed, which could explain the presence of a persistent portal inflammation leading to fibrosis, and the gut-liver axis would also have a role in disease presentation and progression.