[Genetics and pathophysiology of hereditary motor and sensory neuropathy type 1]

Hereditary motor and sensory neuropathy type 1 (HMSN1) is the most common, but genetically heterogenous demyelinating peripheral neuropathy. HMSN1A is caused in most cases by a 1.5-Mb tandem duplication in chromosome 17p11.2. Hereditary neuropathy with liability to pressure palsies is caused by the reciprocal deletion of the 1.5-Mb HMSN1A region. The peripheral myelin protein22 (PMP-22) gene is located within the HMSN1A region and has a point mutation in non-duplicated HMSN1A patients. HMSN1B patients have a mutation in the protein zero (P0) gene located on chromosome 1q22-23 Point mutation in PMP-22 or P0 is also reported in patients with Dejerine-Sottas disease. In X-linked HMSN1 patients (HMSNX1) a mutation occurs in the connexin 32 gene located on chromosome Xq13. The morphological phenotype is different among the genotypes of HMSN1.