Conduction block and tonic pupils in Charcot-Marie-Tooth disease caused by a myelin protein zero p.Ile112Thr mutation

Neuromuscul Disord. 2011 Mar;21(3):223-6. doi: 10.1016/j.nmd.2010.12.010. Epub 2011 Jan 21.


We report a patient with Charcot-Marie-Tooth disease (CMT) due to the p.Ile112Thr mutation in myelin protein zero (MPZ) who presented with a patchy neuropathy with conduction block and tonic pupils. Conduction block is unusual in inherited neuropathies, while pupil abnormalities are recognised to occur in CMT especially due to MPZ mutations. This case highlights that patchy demyelinating neuropathy with conduction block may occur in p.Ile112Thr MPZ mutations. Involvement of the pupils, as in this case, may be a pointer towards a genetic rather than inflammatory cause of neuropathy.

Publication types

  • Case Reports
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Charcot-Marie-Tooth Disease* / genetics
  • Charcot-Marie-Tooth Disease* / pathology
  • Charcot-Marie-Tooth Disease* / physiopathology
  • Humans
  • Isoleucine / genetics*
  • Male
  • Mutation / genetics*
  • Myelin P0 Protein / genetics*
  • Neural Conduction / physiology*
  • Pupil / physiology*
  • Threonine / genetics


  • Myelin P0 Protein
  • Isoleucine
  • Threonine