Unmasking Alagille Syndrome in Adulthood- A Complete Clinical Portrait of a Rare Syndrome

Alagille syndrome (ALGS) is a rare autosomal dominant multisystem disorder characterized by marked phenotypic variability, and the diagnosis is sometimes very challenging. We describe a 26-year-old man who presented with progressive jaundice, pruritus, and weight loss over three months, with a history of similar episodes in early childhood. He had previously been diagnosed with atrial septal defect with severe pulmonary stenosis, myopia, and hypothyroidism. After a thorough Clinical examination which revealed icterus, pedal edema, stigmata of chronic liver disease, and characteristic facial dysmorphism with café-au-lait spots, a possibility of Alagille syndrome was considered. Laboratory evaluation showed cholestatic liver dysfunction and pancytopenia. Whole-exome sequencing identified a likely pathogenic JAG1 variant, and liver biopsy confirmed bile duct paucity. This case highlights the diagnostic challenges of ALGS and underscores the importance of meticulous clinical evaluation and comprehensive longitudinal history-taking, as multiple healthcare encounters preceded the correct diagnosis as far as this patient is concerned.