2 DIVERGENT TYPES OF NERVE PATHOLOGY IN PATIENTS WITH DIFFERENT P-0 MUTATIONS IN CHARCOT-MARIE-TOOTH DISEASE

In seven unrelated patients with a demyelinating motor and sensory neu ropathy, we found mutations in exons 2 and 3 of the P-0 gene. Morpholo gic examination of sural nerve biopsy specimens showed a demyelinating process with onion bulb formation in all cases. In four patients, ult rastructural examination demonstrated uncompacted myelin in 23 to 68% of the myelinated fibers, which is in agreement with the widely accept ed function of P-0 as a hemophilic adhesion molecule. Three patients s howed normal compact myelin, but morphology was dominated by the abund ant occurrence of focally folded myelin. The two divergent pathologic phenotypes exemplify that some mutations act differently on P-0 protei n formation or function than others, which is probably determined by s ite and nature of the mutation in the P-0 gene.