QKI and Ataxia: All Qk-Plp-iCKO mice began to experience tremors and ataxia about 11 days after tamoxifen injection, and they gradually displayed reduced coordinate movement, marked growth retardation, hunched posture, and paralysis before dying about 18 days after tamoxifen injection (Figure 4B–E, Figure 4—figure supplement 1A, Video 2), whereas the control mice (including Plp1-CreERT2;Qk+/+, Plp1-CreERT2;QkL/+, and QkL/L littermates) did not exhibit neurological symptoms after tamoxifen injection at P4.