DMPK and myotonic dystrophy: The unstable CTG repeat expansion in the DMPK gene causes myotonic dystrophy 1,58–61 while a CCTG repeat expansion in the CNBP gene causes myotonic dystrophy 2.62,63 In both diseases, mutant CCUG-expanded RNAs sequester the muscleblind-like family of splicing factors, resulting in inappropriate splicing of various genes.64–66 In ALS, the presence of nuclear RNA foci containing GGGGCC-repeats correlates with inflammation in an interferon-induced manner by activating the protein kinase R stress pathway to enhance toxic peptide-dependent neurodegeneration.67,68