2. Hereditary Myopathies:

These muscle diseases are inherited courtesy of various genetic defects, which are unique for each hereditary muscle disorder. These include following disorders.

A. disorders of dystrophin.

B. Limb girdle muscular dystrophy.

C. Facioscapulohumeral muscular dystrophy.

D. Myotonic muscular dystrophy.

E. Emery-Dreifuss muscular dystrophy.

F. Others.

3. Inflammatory Myopathies:

Systemic inflammation or local inflammation of the muscles themselves leads to rapid weakness and destruction of the muscles. This class includes following varieties.

A. Polymyositis

B. Dermatomyositis.

C. Inclusion Body Myositis.

4. Disorders of Membrane Ion Channels:

These disorders, also known as channelopathies, include following disorders.

A. Periodic Paralysis.

B. Myotonia.