Substantial evidence supports a pathogenic role for these non-coding repeats at the RNA level, such as the discovery of a second type of DM, DM2 (or PROMM, proximal myotonic myopathy), which is due to a CCTG repeat expansion in another non-coding part of another transcript, the first intron of the ZNF9 gene (Liquori et al., 2001). Here, CNBP is linked to myotonic dystrophy type 2.