Alagille syndrome (ALGS) is a rare, multisystem genetic disorder most commonly caused by haploinsufficiency of the JAG1 gene, leading to reduced JAG1 protein function and impaired development of intrahepatic bile ducts. Researchers from Arnatar Therapeutics Inc. described the development of antisense oligonucleotides (ASOs) engineered using their proprietary ACT‑UP1 platform to upregulate endogenous JAG1 expression and thereby address the underlying genetic deficiency.