MBNL1 and myotonic dystrophy type 1: The same group later used adult and neonatal mouse models of DM1 and demonstrated that intramuscular or systemic injections of adeno-associated virus (AAV) vectors encoding nuclease-dead Cas9 and a single guide RNA targeting CUG repeats resulted in the expression of the RNA-targeting Cas9 for up to 3 months, redistribution of the MBNL1, elimination of foci of toxic RNA, reversal of splicing biomarkers and amelioration of myotonia [104].