Myotonic dystrophy Type 1 is caused by a mutation in the DMPK gene. Type 2 myotonic dystrophy is caused by a mutation in the CNBP gene. Mutations in each of these genes involve a short segment of DNA that is abnormally repeated many times. This abnormal repetition forms an unstable region of the gene.

What is the cause of myotonic dystrophy?

Myotonic dystrophy is caused by mutations (changes) in the DMPK gene or the CNBP (ZNF9) gene depending on the specific type of myotonic dystrophy. The disease is inherited in an autosomal dominant manner.

Who is most likely to get myotonic dystrophy?

DM is the most common muscular dystrophy among adults of European ancestry. The prevalence of DM is about 10 cases per 100,000 individuals. Among nonwhite populations, DM1 is uncommon or rare.