Two types of Charcot-Marie-Tooth Disease: Type I and Type II.

Charcot-Marie-Tooth Disease Type I is the most frequent form, is a demyelinating polyneuropathy (with reduced nerve conduction velocity) caused by mutations affecting myelin components.

Charcot-Marie-Tooth Disease Type II is an axonal polyneuropathy (with normal nerve conduction velocity) determined by defects in axonal transport (mutation of a kinesin), membrane trafficking, and protein synthesis.

Myelin protein zero (MPZ) is a member of the immunoglobulin superfamiliy with a dual role; the compactation of myelin and cell signaling.

A duplication of the peripheral myelin protein 22 (PMP22) gene causes Charcot-Marie-Tooth Disease Type 1A, the most common type of Charcot-Marie-Tooth Disease.

- Charcot-Marie-Tooth Disease comprises a heterogenous group of inherited peripheral neuropathies.  Approximately 1 in 2500 persons has some form of the disease, making it one of the most frequently occurring inherited neurological syndromes. 
- Transmission is most frequently autosomal dominant but may also be autosomal recessive or X-linked, like the mutation affecting the connexin 32 (Cx32), located in the folds of the Schwann cell cytoplasm around the nodes of Ranvier.  This localization suggests a role for gap junctions composed of Cx32 in ion and nutrient transfer around and across the myelin sheath of peripheral nerves.