Hepatic ductular hypoplasia, syndromatic: Also called Alagille syndrome or arteriohepatic dysplasia, this is a genetic disorder characterized by jaundice in the newborn period, liver disease with cholestasis, peripheral pulmonic stenosis and unusual face. Children with Alagille syndrome usually present with jaundice (yellowing of the skin and whites of the eyes) in the newborn period. Cholestasis (stagnant flow of bile from the liver) then develops with puritis (itching), stools without the usual yellowing brown color, and enlargement of the liver and spleen. Peripheral pulmonic stenosis is a form of congenital heart disease (CHD). Other types of CHD also occur. The face has deep-set eyes, broad forehead, long nose with flat tip, prominence of the chin, and low-set or malformed ears. The outlook (prognosis) depends upon the degree of severity of the CHD and the liver disease (it can cause liver failure). The condition is an autosomal dominant trait meaning that the gene for it is on a non-sex chromosome (an autosome) and a single edition of the Alagille gene is sufficient to produce the disease. The gene has been discovered on chromosome 20 in band 20p12. The syndrome was first described by D. Alagille in the French medical literature in 1969.