It is known as Hereditary motor and Sensory neuropathy (HMSN). It is slowly progressive neuropathy that affects peripheral nerves and causes sensory loss, weakness and muscle wasting in distal musculature of feet, lower legs, hands and forearm. It is often misdiagnosed as orthopedic condition but it is most frequent type of neuropathy.

It was first described in 1886 by Jean Marie Charcot, Pierre Marie and Howard Henry Tooth. So it is named Charcot Marie Tooth disease. Its incidence rate is 1 in 2500 person.

As it is hereditary in nature the cause lies in PMP22 gene. This gene is located on 17p.12.chromosome. This gene provides instruction for making a protein called peripheral myelin protein 22 which is found in peripheral nervous system. Due to copy number variation in PMP22 gene it leads to demyelination and axonopathy in peripheral nerves. Due to immune mediated mechanism, acceleration of pathology is seen.

There are 4 types of CMT on basis of mode of inheritance and clinical features :

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CMT 1	CMT 2	CMT 3	CMT 4
Demyelinating form	Axon affection	Dejerene sottas disease	Refsum disease
Autosomal dominant	Autosomal dominant	Autosomal dominant	Autosomal recessive
Childhood or adolescence onset	Childhood or adolescence onset	Congenital
		Hypomyelination

Distal symmetrical weakness, wasting, hypo/areflexia are common symptoms of all CMTs. Symptoms begin in feet with foot drop. Later in course weakness starts in hands and forearms. Many patients develop pes cavus, hammer toe, clawed hand, contractures in long finger flexors and scoliosis. The parents or patient describes initial symptoms as difficulty in walking fast or running, tripping, falls, twisting of ankles and calf cramps. During childhood they are clumsy and avoid sports. Weakness in hands leads to difficulty in performing fine motor activities.

Decreased sensation to heat, touch, pain and most prominently vibration in the distal extremities. High steppage gait develops due to deformities and Proprioceptive loss. The symptoms varies according to the types of CMT but the above are the most common.

Electrophysiology study, nerve imaging, genetic testing, nerve biopsy and evaluation of systemic involvement are the most commonly done investigation done in CMT.

Treatment is mostly rehabilitative and symptomatic since no disease modifying drug are there which alter the natural progress. Researchers are going on for finding the cure. Some have found promising results but in small population. So physical therapist and occupational therapist can help to increase the quality of CMT people.

According to researches there is no single protocol for this patient. Consistency in performing physiotherapy plays major role. Strength training, stretching, Proprioceptive training, endurance, aerobic exercise, balance training, walking on treadmill and therapeutic games are main rehabilitative measures. Orthosis like spinal, AFO, thumb opposition splint, serial night cast and derby shoe also helps to correct or prevent skeletal deformities.