EDITOR—Myotonic dystrophy (DM) is the most common form of inherited neuromuscular disease in adults and is characterised by progressive muscle wasting and myotonia. The mutation responsible for DM has been identified as the amplification of a polymorphic (CTG)n repeat in the 3' untranslated region of a gene encoding a serine/threonine kinase (DMPK). The DM trinucleotide repeat is highly polymor...
