MBNL1 and Myotonia: More recently, Batra and colleagues demonstrated that muscular or systemic injections of AAV vectors encoding nuclease-dead Cas9 and a single-guide RNA targeting CUG repeats results in the expression of the RNA-targeting Cas9 for up to three months, redistribution of MBNL1, elimination of foci of toxic RNA, rescue of splicing defects and amelioration of myotonia [125].