Alagille syndrome is a genetic disease with multi-organ involvement and can cause various congenital cardiac lesions. This syndrome is caused by mutations in the JAG1 and NOTCH gene pathways. As a result of these lesions, pulmonary hypertension can be seen in patients. While pulmonary hypertension is observed especially due to pulmonary valve stenosis; It may be due to various causes such as tetralogy of Fallot. Currently, pulmonary hypertension has not been reported in Alagille patients without cardiac anomaly in the literature.