Neonatal hemochromatosis: a congenital alloimmune hepatitis.

Neonatal hemochromatosis (NH) is a rare and enigmatic disease that has been clinically defined as severe neonatal liver disease in association with extrahepatic siderosis. It recurs at an alarming rate in the offspring of certain women; the rate and pattern of recurrence led us to hypothesize that maternal alloimmunity is the likely cause at least of recurrent cases. This hypothesis led to a trial of gestational treatment to prevent the recurrence of severe NH, which has been highly successful adding strength to the alloimmune hypothesis. Laboratory proof of an alloimmune mechanism has been gained by reproducing the disease in a mouse model. NH should be suspected in any very sick newborn with evidence of liver disease and in cases of late intrauterine fetal demise. Given the pathology of the liver and the mechanism of liver injury, NH could best be classified as congenital alloimmune hepatitis.