One or more embodiments of the present invention include an immunodeficient mouse genetically modified to include a gene encoding a PiZ variant (Glu342Lys) of human α-1 antitrypsin (AAT), wherein the mouse expresses the PiZ variant of human α-1 antitrypsin (Z-AAT), and has a reduced number of mouse hepatocytes compared to an immunodeficient mouse of the same type which does not express Z-AAT. The immunodeficient mouse genetically modified to include a gene encoding a PiZ variant of human AAT can be a genetically modified NSG, NRG or NOG mouse. The immunodeficient mouse may further include xenogeneic hepatocytes, such as human hepatocytes. Putative treatments of human liver disease can be assessed in mice provided according to aspects of the present disclosure.
