QKI and Tremor: About 12 days after tamoxifen injection, Nestin-CreERT2;QkL/L mice (hereafter denoted as ‘Qk-Nestin-iCKO mice’) began to exhibit visible tremors and ataxia accompanied by a significant reduction in coordinate movement as measured using the rotarod test and a marked growth retardation (Figure 1B–D, Figure 1—figure supplement 1A, Video 1).