Myotonic muscular dystrophy

Myotonic muscular dystrophy (DM) is the most common cause of inherited muscular dystrophy affecting adults and children. It is inherited as an autosomal dominant trait but exhibits a remarkable degree of variable expressivity and penetrance, even within a single family. DM is more than a muscular dystrophy because it commonly affects multiple systems including muscle, brain, heart, gastrointestinal, endocrine, and bone. Because DM is a common disorder and transmitted as a dominant trait, it is well suited for genetic study. This article will review the clinical manifestations and molecular genetics of DM, focusing on the genetic research strategies and recent advances into the cause of DM.