PROJECT SUMMARY Hereditary tyrosinemia type 1 (HT1) is an autosomal recessive metabolic liver disease that can cause death in the first months of life and incurs an increased risk of hepatocellular cancer. The current treatment option—strict adherence to twice daily dosing with NTBC, a repurposed herbicide that inhibits HPD—is limited by high noncompliance rates. Liver transplant remains the only option for those patients that fail medical management. Genome editing to inactivate the HPD gene in the tyrosine catabolic pathway provides a potential universal, one- time, lifelong treatment for HT1 patients. Project 2 will focus on an LNP-based adenine base editing postnatal treatment of HT1, with the aim to file an IND application and begin a clinical trial, and prenatal base editing treatment of HT1, with the aim of performing preclinical studies during the five-year funding period to enable an eventual IND application if the postnatal clinical trial proves successful.