Although DM1 is caused by a DMPK 3’ untranslated region (3’UTR) CTGexp and DM2 by an intronic CCTGexp in CNBP, they share a number of pathological features including skeletal muscle myotonia and weakness/wasting, heart conduction block, unusual dust-like ocular cataracts and cognitive dysfunction (Figure 2). Here, CNBP is linked to myotonic dystrophy type 1.