Expression of P0 protein in sural nerve of a patient with hereditary motor and sensory neuropathy type III.

We present expression of Po protein and Po mRNA on the sural nerve of a patient with hereditary motor and sensory neuropathy type III. This patient was identified with a point mutation in Po gene, which resulted in the substitution of glycine for arginine in transmembrane domain of P0 protein. An electron microscopic examination revealed very thin myelinated fibers surrounded by multilamellated onion bulbs composed with greatly proliferated Schwann cells. An immunocytochemical and immunoblot analysis is showed P0 protein normally expressed in myelin on the sural nerve. By in situ hybridization, mRNA of P0 protein was detected at normal levels in Schwann cell cytoplasm. Those observations indicated that there was no truncated myelin P0 protein in peripheral nerve of this patient.