Topic: Myotonic dystrophy type 1

Expanded CAG/CTG repeats cause at least 15 different neurodegenerative and neuromuscular diseases that all remain without an effective disease modifying treatment. Because the size of the repeat tract accounts for the majority of the variation in disease severity, contracting them presents an attractive therapeutic avenue. Here, we show that the CRISPR-Cas9 nickase targeted to the CAG/CTG repeat itself leads to efficient contractions in Huntington’s disease patient-derived neurons and astrocytes as well as in myotonic dystrophy type 1 patient-derived neurons. Using single-cell DNA sequencing a

Genetically, myotonic dystrophy type 1 (DM1) is caused by a pathological CTG-repeat expansion in the 3′UTR of the DMPK gene. The mRNA containing the extended repeat is described to be toxic and forms foci with RNA-binding proteins like MBNL1-3. Here, our objective is to employ Cas13b-mediated cleavage to knock down the DMPK in DM1 patient muscle cells. Primary myoblasts from controls and DM1 patients were immortalized using lentiviral transduction of CDK4 and hTERT to generate comparable cell lines. Immortalized myoblasts were transduced with adeno-associated virus (AAV) vectors containing Cas