Myotonic dystrophy, type 2 (DM2) is an autosomal dominant disorder caused by expansion of the CCTG repeats in the zinkfinger protein-9 gene (ZNF9). It has been clinically reported in the middle 1990th. DM2 is less frequent than “classic” DM1, yet is relatively common, mostly in Europeans. Like DM1, DM2 is a multisystem disorder, and main distinctions from DM1 are: relatively late onset, proximal character of myopathy, less severe myotonia, presence of myalgia, etc. Clinical features complicate the diagnosis, and a number of cases cannot be identifiedon time. In the Research Centre for Medical Genetics the DNA diagnostics of DM2 is now available, and several cases have been confirmed molecularly.