The B6-hC3 mouse is a mouse C3 humanized model created by replacing the mouse C3 gene with the human C3 gene using gene-editing technology. The humanized regions include the 5’UTR and 3’UTR. Under natural breeding conditions, homozygous B6-hC3 mice exhibit mortality around 10 weeks of age, and it has been observed that heterozygous mice also experience mortality.