To assess the potency of all-LNA oligomers in a physiologically relevant model of DM1, we employed three DM1 patients-derived fibroblast cell lines expressing mutant DMPK transcripts with ∼500, ∼1000 and ∼2000 CUG repeats, referred to as (CUG)500, (CUG)1000 and (CUG)2000, respectively. Here, DMPK is linked to myotonic dystrophy type 1.