These KI mouse lines express physiological levels of cervid PrPC (in comparison to wild-type C57BL/6), and preliminary data suggested that KI mice replicate CWD prions upon peripheral challenge, reaching terminal prion disease endpoints at 400–600 days post-inoculation [189], with the typical CWD signs as seen in other CWD mouse models. The gene discussed is PRNP; the disease is prion disease.