Introduction

Muscular dystrophies are a group of inherited muscle disorders that lead to muscle weakness (see Section 5, Chapter 59) of varying severity. Other inherited muscle disorders include myotonic myopathies, periodic paralysis, and glycogen storage diseases. Glycogen storage diseases are a group of rare inherited disorders in which muscles cannot metabolize sugars normally (see Section 23, Chapter 282), so they build up large stores of glycogen (a starch that is formed from sugars).