Nerve conduction abnormalities in the trembler-j mouse: a model for Charcot-Marie-Tooth disease type 1A?

The trembler-j mouse is a spontaneously occurring, demyelinating mutant secondary to a point mutation involving a leucine for proline substitution in the first transmembrane domain of the peripheral-myelin protein-22 (PMP-22) gene. It is considered to be a model for Charcot-Marie-Tooth disease type 1A (CMT1A), largely based upon pathologic observations. However, functional studies demonstrating homology with CMT1A patients have not been documented. Sciatic nerve conduction was performed on 30 and 72-day-old wildtype and trembler-j mice in a blinded fashion. The findings in the mutants in both age groups were consistent with profound demyelination. Trembler-j mice appear to have a greater degree of motor nerve conduction slowing relative to human studies involving patients with PMP-22 gene duplication. Functionally, the trembler-j is a good murine model for CMT1A associated with an identical point mutation but may represent a more severe disease phenotype than CMT1A secondary to PMP-22 gene duplication.