With transition to the genetic era, the number of muscular dystrophies has grown significantly, but so too has our understanding of their pathogenic underpinnings. Clinical features associated with each muscular dystrophy still guide us to the diagnosis. However, improved diagnostic abilities refine and expand phenotypic and genotypic correlates. This article discusses the epidemiology, clinical features, and diagnosis of these disorders.
Some important recent advancements include (1) a much greater understanding of the pathogenetic pathways underlying facioscapulohumeral muscular dystrophy and myotonic dystrophy type 1; (2) the publication of diagnostic and treatment guidelines for Duchenne muscular dystrophy; and (3) further clarification of the many genetic muscle disorders presenting a limb-girdle pattern of weakness.
Muscular dystrophies are genetic, progressive, degenerative disorders with the primary symptom of muscle weakness. Duchenne, Becker, facioscapulohumeral, and myotonic muscular dystrophies are most prevalent and tend to have distinctive features helpful in diagnosis. The limb-girdle, Emery-Dreifuss, and oculopharyngeal muscular dystrophies are less common but often may also be diagnosed on the basis of phenotype. Researchers hope to help patients with future discoveries effective in slowing or halting disease progression, reversing or preventing underlying mechanisms, and repairing previously damaged muscle.
Address correspondence to Dr Matthew Wicklund, Penn State Hershey Medical Center, Department of Neurology-EC037, 30 Hope Drive, Hershey, PA 17033, email@example.com.
Relationship Disclosure: Dr Wicklund has participated as a site investigator for clinical trials sponsored by Eli Lilly and Company and Genzyme Corporation.
Unlabeled Use of Products/Investigational Use Disclosure: Dr Wicklund discusses the unlabeled use of prednisone, prednisolone, and deflazacort for the treatment of Duchenne muscular dystrophy and of mexiletine for the treatment of myotonia in myotonic dystrophy.