Myotonic Dystrophy

Myotonic dystrophy (dystrophia myotonica, myotonia atrophica) is a chronic, slowly progressing, highly variable, inherited multisystemic disease.

It is characterized by wasting of the muscles (muscular dystrophy), cataracts, heart conduction defects, endocrine changes, and myotonia. Two types of myotonic dystrophy exist.

Myotonic dystrophy type 1 (DM1), also called Steinert disease, has a severe congenital form and a milder childhood-onset form. Myotonic dystrophy type 2 (DM2), also called proximal myotonic myopathy (PROMM) or adult-onset form, is rarer than DM1 and generally manifests with milder signs and symptoms. Myotonic dystrophy can occur in patients of any age. Both forms of the disease display an autosomal dominant pattern of inheritance.