Approximately 3 weeks after birth, CTCF-cKO mice, represented by the genotype Ctcf;Grid2-Cre (fl/fl; +/Cre), showed obvious differences in appearance with growth retardation and ataxia-like motor abnormalities as compared with mice of other genotypes (Fig. 1b, c). This evidence concerns the gene GRID2 and cerebellar ataxia.