A mutant protein has been identified by scientists as culprit in Charcot-Marie-Tooth (CMT) diseases. CMT is a group of hereditary disorders that affects about 1 in every 2,500 people in the United States, making it one of the most common inherited neurological diseases. While different forms of the disease vary in their symptoms and underlying genetic causes, the common thread is that CMT damages the nerves in a person's arms and legs.