However the trans acting factors that bind the CUG repeats and that are reported to be implicated in DM1 [10] have homologues in Drosophila, like CUG-BP1 [36], hnRNP H [37] whereas the muscleblind gene was first identified in Drosophila[38]. The gene discussed is CELF1; the disease is myotonic dystrophy type 1.