Thus these results demonstrate that although increased steady state levels of CUG-BP1 is sufficient to produce features of DM1, elevated CUG-BP1 levels may not be required for DM1 pathology to manifest, as reduction of CUG-BP1 levels does not correct the splice defects in DM1 myoblasts. This evidence concerns the gene CELF1 and myotonic dystrophy type 1.