TJ disruption is an emerging pathology in a variety of diseases55, 56, including: altered TJ-associated ZO-1 protein localization in gut tissue, in both non-alcoholic fatty liver disease (NAFLD) and steatohepatitis; microbial pathogenesis53, such as TJ-mediated viral entry in hepatitis; cancer development and metastasis; cholestatic drug hepatoxicity2, 3; and genetic-based (TJ-associated Claudin-1 mutations) liver disease (neonatal ichthyosis and sclerosing cholangitis syndrome). The gene discussed is TJP1; the disease is metabolic dysfunction-associated steatotic liver disease.