Neurológia pre prax 6/2016

Hereditary motor neuropathies

The hereditary motor neuropathies (HMN), sometimes called distal spinal muscular atrophies (dSMA), are characterized by selective involvement of peripheral motor nervous system. They affect about 10% of all patients suffering from hereditary neuropathies. The typical clinical features are symmetric atrophies and weakness of distal muscles of all extremities in lenght dependent pattern. They are clinically and genetically heterogeneous group of motor neuropathies with great diversity of phenotype and genotype. This group was subdivided into different types according to age of onset, muscle weakness distribution at upper or lower limbs, minor sensory impairment, neuromyotonia or vocal cord paralysis. Recently, more than 12 genes were discovered and are considered as a cause of different type of HMN. The diagnostic algorithm include clinical symptoms, electrophysiology and molecular genetic testing. The differential diagnosis is very important and similar conditions are considered, g.e. Charcot-Marie-Tooth disease, motor neuron diseases, including juvenile forms of amyotrophic lateral sclerosis or acquired multifocal motor neuropathy. The causative treatment is not available. The physiotherapy, orthotics and orthopedic surgery are important. The genetic counselling, prenatal or preimplant genetics testing are very important in the case of known causative mutation.

Keywords: hereditary neuropathies, Charcot-Marie-Tooth disease, genetics, neuropathy