The myotonic dystrophies

Abstract

The myotonic dystrophies (DM) are multisystem disorders affecting the skeletal muscle, heart, smooth muscle, skin, eyes, and the endocrine system. Two genetic mutations are known to cause DM (DM1 and DM2). DM2 provides an important second example of a multisystem disease and is generally less severe than DM1. This chapter discusses the clinical and laboratory findings of DM1 and DM2 and their subtypes including the pathophysiology, emerging genetic findings, and treatment.