Alagille syndrome (MONDO_0007318, a Monarch Disease Ontology id) can be described as follows. Alagille (AGS) syndrome is variably characterized by chronic cholestasis due to paucity of intrahepatic bile ducts, peripheral pulmonary artery stenosis, vertebrae segmentation anomalies, characteristic facies, posterior embryotoxon/anterior segment abnormalities, pigmentary retinopathy, and dysplastic kidneys. Also known as: Alagille-Watson syndrome, Arteriohepatic dysplasia, syndromic bile duct paucity.