CELF1 and myotonic dystrophy type 1: In contrast, CUGBP1 does not colocalize with ribonuclear foci in DM1 cells [9], [13], [14], however this protein may have a role in the pathogenesis of splicing abnormalities because it is overexpressed in DM1 myoblasts, skeletal muscle and heart tissues [15]–[17].