These involuntary contractions arise in response to voluntary muscle use or percussion of the muscle. Clinically myotonic dystrophy is classified as a muscular dystrophy although the disease mechanism is distinct from that of the other muscular dystrophies.
Myotonic dystrophy is distinct in having widespread effects throughout the systems of the body.
That this disease primarily affects muscle and not nerve was shown by Denny-Brown and Nevin in 1941. The tendency of the disease to become more severe with successive generations, called anticipation, was recognized by Fleischer in 1918. The genetic basis for the disease was elicited in 1992. Clinical Presentation Epidemiology Myotonic dystrophy occurs in one per 8,000 live births. It is among the more common inherited neurological disorders and occurs equally in men and women.