Myotonic Dystrophy Type 1: Focus on the RNA Pathology and Therapy

Almost 100 years ago, Steinert (1909), Batten and Gibb (1909), independently described Myotonic Dystrophy type 1 (DM1) that is now recognized as the most common form of muscular dystrophies in adults and the second most common type of muscular dystrophy after Duchenne Muscular Dystrophy, affecting 1 in 8000 individuals globally (Harper, 1989). DM1 is a genetic disorder, which is inherited in an autosomal dominant fashion (the mutation in one copy of the affected allele is enough to cause the disease). Although the disease affects mainly the skeletal muscle, it is considered a multi-systemic disorder with variable clinical symptoms affecting skeletal muscle, heart, and the central nervous system (CNS) (Larkin & Fardaei, 2001). Individual patients with DM1 are often identified as having congenital, juvenile or adult-onset disease based on the age of symptom onset. Congenital cases display the most severe phenotype and face a neonatal mortality rate of 25% (Harper, 1989).