Natural History of Liver Disease in a Large International Cohort of Children with Alagille syndrome: Results from The <scp>GALA</scp> Study

Background: Alagille syndrome (ALGS) is a multisystem disorder, characterized by cholestasis. Existing outcome data are largely derived from tertiary centers and real-world data are lacking. This study aimed to elucidate the natural history of liver disease in a contemporary, international, cohort of children with ALGS. Methods: Multicenter retrospective study of children with a clinically and/or genetically confirmed ALGS diagnosis, born Jan-1997 - Aug-2019. Native liver survival (NLS) and event-free survival rates were assessed. Cox models were constructed to identify early biochemical predictors of clinically evident portal hypertension (CEPH) and NLS. Results: 1433 children (57% male) from 67 centers in 29 countries were included. 10 and 18-years NLS rates were 54.4% and 40.3%. By 10 and 18-years, 51.5% and 66.0% of ALGS children experienced ≥1 adverse liver-related event (CEPH, transplant or death). Children (>6 and ≤12 months) with median total bilirubin (TB) levels between ≥5.0 and <10.0 mg/dL had a 4.1-fold (95% CI 1.6 - 10.8) and those ≥10.0 mg/dL had an 8.0-fold (95% CI 3.4 - 18.4) increased risk of developing CEPH compared with those <5.0 mg/dL. Median TB levels between ≥5.0 and <10.0 mg/dL and >10.0 mg/dL were associated with a 4.8 (95% CI 2.4 - 9.7) and 15.6 (95% CI 8.7 - 28.2) increased risk of transplantation relative to <5.0 mg/dL. Median TB <5.0 mg/dL were associated with higher NLS rates relative to ≥5.0 mg/dL, with 79% reaching adulthood with native liver (p<0.001). Conclusions: In this large international cohort of ALGS, only 40.3% of children reach adulthood with their native liver. A TB <5.0 mg/dL between 6-and-12-months of age is associated with better hepatic outcomes. These thresholds provide clinicians with an objective tool to assist with clinical decision-making and in the evaluation of novel therapies.