RESUMEN
Alagille syndrome is a complex autosomal dominant disorder secondary to defects in the Notch signaling pathway, primarily caused by mutations in the Jagged1 (JAG1) gene. The liver, heart, skeleton, face and eyes are the body parts most commonly involved. Alagille syndrome may mimic other causes of high gamma-glutamyl transferase (GGT)-linked cholestasis, most notably biliary atresia in the neonatal period. Infants with Alagille syndrome are occasionally misdiagnosed as cases with biliary atresia due to variations in clinical features that might be expressed in early infancy. We describe a case of Alagille syndrome mimicking biliary atresia, identified by sequencing analysis of the JAG1 gene in a newborn. During counseling, family members of the patient have also been found to demonstrate various phenotypes and levels of disease severity of Alagille syndrome.