Advances in myotonic dystrophy: a clinical and genetic perspective.

The recent identification of the gene responsible for myotonic dystrophy and the recognition of an expanding unstable repeat sequence as the specific molecular defect, have resulted in rapid changes in clinical practice as well as in our understanding of the disorder. Against such a framework, this review traces the evolution of clinical and genetic knowledge of the disorder and emphasizes the continuing central role of thorough clinical investigation of those at risk for carrying the gene as an essential element of predictive testing for myotonic dystrophy.