Hereditary motor and sensory neuropathies (HMSN) are a group of neuropathies which are characterized by their impact upon both afferent and efferent neural communication. HMSN are characterized by non typical neural development, and degradation of neural tissue. The two common forms of HMSN are either hypertrophic demyelinated nerves or complete atrophy of neural tissue. Hypertrophic condition causes neural stiffness and a demyelination of nerves in the peripheral nervous system, and atrophy causes the breakdown of axons and neural cell bodies.