Clinical aspects and diagnostic and therapeutic approaches to motor and sensory hereditary neuropathies

Introduction. The classifications of peripheral neuropathies are continually being revised in the light of advances in genetic and biochemical investigation. Objective. We establish a classification based on the pathology found in different anatomical structures of nerves: the Schwann cell, myelin, axon and the different genes involved in causing neuropathies. Diagnosis is based on data from the clinical history, physical examination and electromyography and their correlation with the type of inheritance in relation to the different genes localized to (a) the Schwann cell: periaxin gene (PRX) encoding L and S periaxin. Stabilisation of the myelin acting as a signal tranducer. NDRG1 down stream regulated gene 1 and 2 acting as transcription factors in embryogenesis. EGR2/Krox 20 has an important function in myelinization. (b) Myelin: P0 membrane protein zero (MPZ) stabilizes the myelin. P1 myelin basic protein (MBP), is analogous to the myelin protein of the central nervous system (CNS) P2 found in the cytoplasm. PMP22 (peripheral myelin protein) also stabilizes the protein. MAG (myelin associated glycoprotein) has antigenic properties. (c). Axon. A foundational mutation (892C-Y) in the gene of the lamina (LMNA) of the light neurofilaments (NF-L). Mutations in the KIF1Bbeta gene which encodes the protein kinesin. We also make an aetiological analysis of some classical syndromes, especially the Dejerine-Sottas syndrome. Conclusion. The systematization used, based on clinical and electrophysiological data in relation to the different genes involved in the various anatomical structures constitutes a logical, diagnostic approach which is very useful.