The F9 gene is located on the X chromosome. In this F9 knockout mouse model, gRNAs were designed targeting exon8 of F9 gene via CRISPR gene editing technology. Loss of F9 caused coagulopathy in mice. Mice that are homozygous for F9 knockout are viable, fertile and normal in size. Normal fighting in the cage may cause bleeding or even death due to massive internal hemorrhaging. After the tail cutting, wounds must be cauterized to prevent homozygous knockout mice from blood loss and death. This strain is a powerful model for studying coagulopathy, gene therapy methods and function of factor IX mutations. Click here for detailed information.