Deletion in chromosome 17p11.2 including the peripheral myelin protein-22 (PMP-22) gene in hereditary neuropathy with liability to pressure palsies.

We report the clinical, electrophysiological, and pathological findings of two unrelated Japanese families with hereditary neuropathy with liability to pressure palsies (HNPP) and confirm the findings of a deletion of peripheral myelin protein-22 (PMP-22) gene. Electrophysiological studies revealed slowing of nerve conduction velocities of the affected nerves. Sural nerve biopsy revealed regions of myelin duplication. The copy numbers of PMP-22 gene was lower than that of normal control, suggesting deletion of 17p11.2 including PMP-22 gene. Our results indicate that HNPP in these two Japanese families is attributable to deletion of 17p11.2 including PMP-22 gene.