Charcot-Marie-Tooth disease (CMT) is a hereditary sensorimotor polyneuropathy which is occasionally associated with demyelinating lesions in the central nervous system, although it remains unclear whether this finding is coincidental or whether the two processes share a common pathogenic mechanism.
A male patient with sensorimotor polyneuropathy presented with symptoms consistent with cauda equina syndrome at age 47 in relation to an inflammatory lesion in the conus medullaris. Six years later, he presented with sudden-onset neurological symptoms including dysarthria and right hemiparesis. Brain MRI revealed multiple inflammatory/demyelinating lesions. In both episodes, the CSF study showed mild hyperproteinorrachia without pleocytosis or oligoclonal IgG bands (OCBs), and the patient showed good response to corticosteroids. Genetic analysis revealed a duplication of region 17p11.2 of the PMP22 gene, typical of CMT1A.
Current clinical and experimental data appear to support an association between demyelinating diseases of the peripheral and central nervous systems based on the expression of common proteins that may function as target antigens and therefore direct the immune response against both neurological systems. This appears to be the case in CMT1A in which PMP22 is expressed in peripheral nerve myelin, in the brain and in the spinal cord.