Reconstructing Myotonic Dystrophy

Abstract
The genetic mutation in myotonic dystrophy type I (DM1) was identified almost 10 years ago. But how this mutation, an expanded CTG repeat in the DMPK gene, results in disease pathogenesis has remained unclear largely because the expanded repeat is in the non-coding part of the gene. As Tapscott and Thornton explain in their Perspective, the discovery of the DM2 mutation ( Liquori et al.)--a CCTG repeat expansion in the noncoding region of the ZNF9 gene--confirms that there is a common pathogenesis pathway in both forms of DM. It now seems that the disease pathology is attributable at least in part to effects of the repeat-containing RNA transcripts.