Correlation between PMP-22 messenger RNA expression and phenotype in hereditary neuropathy with liability to pressure palsies

Ann Neurol. 1997 Dec;42(6):866-72. doi: 10.1002/ana.410420607.


Hereditary neuropathy with liability to pressure palsies (HNPP) is associated with a deletion in chromosome 17p11.2, which includes the gene for the peripheral myelin protein 22 (PMP-22). A "gene dosage" effect is probably the mechanism underlying HNPP, but the amount of PMP-22 mRNA in sural nerves of HNPP patients is highly variable and the role of PMP-22 underexpression in impairing myelination has yet to be clarified. We have studied 6 genetically proven HNPP patients, to evaluate the relationship between PMP-22 mRNA levels, and clinical, neurophysiological, and neuropathological findings. Underexpression of PMP-22 mRNA correlates with disease severity and with mean axon diameter and g ratio, but not with myelin thickness, number of "tomacula," or nerve conduction parameters. Our findings further confirm that underexpression of PMP-22 is the main pathogenetic mechanism underlying the severity of clinical symptoms and signs in HNPP. Smaller axons in sural nerves of HNPP patients with lower PMP-22 levels suggests that underexpression of PMP-22 may also affect axon development.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Charcot-Marie-Tooth Disease / genetics*
  • Charcot-Marie-Tooth Disease / pathology
  • Charcot-Marie-Tooth Disease / physiopathology
  • Down-Regulation
  • Humans
  • Myelin Proteins / biosynthesis*
  • Phenotype
  • Polymerase Chain Reaction / methods
  • RNA, Messenger / analysis*
  • RNA-Directed DNA Polymerase
  • Severity of Illness Index
  • Sural Nerve / metabolism


  • Myelin Proteins
  • PMP22 protein, human
  • RNA, Messenger
  • RNA-Directed DNA Polymerase