Hereditary neuropathies
Last reviewed: 23.04.2024
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Sensory motor neuropathies
There are three types (I, II and III) that begin in childhood. Rarely occurring types debut from birth and lead to more severe disability.
Types I and II (peroneal amyotrophy, Charcot-Marie-Toot disease, or CMD disease) are the most common, with an autosomodominant type of inheritance. Typical weakness and atrophy, mainly the peroneal and distal muscles of the legs. The patient or his family history may also have other degenerative diseases (for example, Friedreich's ataxia). Illness of type I CMT debuts in childhood with weakness in the feet and slowly progressing distal amyotrophy (stork's legs). Characteristic amyotrophy of the hand develops later. Vibration, temperature and pain sensitivity are violated by the type of stocking - glove.
Deep tendon reflexes fall out. Sometimes the only signs of the disease - deformities of the feet (high arch down to the "hollow" foot) with hammer-shaped deformation of the toes. The speed of conduction of nerve impulses is slowed, and the distal latency is lengthened. There is segmental demyelination and remyelination. It is possible to palpate thickened peripheral nerves. The disease progresses slowly and does not decrease life expectancy. The disease of type II CMT progresses more slowly, the weakness develops later. The rate of excitation is relatively normal, but the amplitude of action potentials of sensitive nerves is reduced, polyphase potentials of muscle action are determined. On biopsy, Waller's degeneration of axons.
Type III (hypertrophic neuropathy, Dejerine-Sott disease) is a rare autosomal recessive disease, begins in childhood with progressive weakness, loss of sensitivity and the absence of deep tendon reflexes. At first it resembles the disease of CMT, but muscle weakness progresses faster. Demyelination - remyelination lead to a thickening of the peripheral nerves, as seen in the biopsy material.
Hereditary motor neuropathy with a tendency to paralysis from compression is a hereditary disease in which the nerves become more sensitive to pressure and stretching.
With hereditary motor neuropathy with a tendency to paralysis from compression, the nerves lose myelin sheath and the ability to conduct pulses normally. The incidence is 2-5 cases per 100 000 inhabitants.
The reason for the loss of one copy of the peripheral myelin protein 22 (PMR22) gene located on the short arm of the chromosome 17. For normal functioning, 2 copies of the gene are needed. At the same time, duplication (the appearance of an additional copy of the gene) is manifested by the development of a type I CMT disease.
The paralysis of the squeezing can be light or heavy and last from a few minutes to months. In the affected areas, numbness and weakness are noted.
This disease should be suspected against a background of recurrent demyelinating polyneuropathy, compression mononeuropathy, multiple neuropathy of unknown origin or carpal tunnel syndrome in a family history. EMG, nerve biopsy and genetic testing help in diagnosis, but biopsy is rarely required. Treatment is symptomatic, it is necessary to avoid all forms of activity that lead to the appearance of complaints. Shinning brushes can reduce pressure, prevent repeated damage and allow after a while to restore myelin. In rare cases, an operation is indicated.
Sensory Neuropathies
With rare hereditary sensory neuropathies, the loss of pain and temperature sensitivity in the distal sections is more pronounced than the loss of vibrational sensitivity and sense of localization. The main complication is foot mutation due to lack of sensitivity, which is fraught with risk of infection and osteomyelitis.
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Treatment of the hereditary neuropathies
Specific treatment does not exist. Adjusting the weakness of the foot helps fixing, and orthopedic surgery can stabilize the foot. To prepare young patients for the progression of the disease, counseling of a medical psychologist is helpful.