The electrodiagnostic findings in polyneuropathies associated with IgM monoclonal gammopathies

Muscle Nerve. 1990 Dec;13(12):1113-7. doi: 10.1002/mus.880131205.


Electrodiagnostic studies were analyzed in patients with neuropathy associated with IgM monoclonal proteins, 7 with anti-myelin associated glycoprotein reactivity (MAG) and 7 nonreactive to MAG. The findings were distinctly different in the two groups. The electrodiagnostic studies of all the MAG-reactive patients had demyelinating features with slowing of conduction and prolonged distal latencies while only one of the MAG-nonreactive patients had a demyelinating pattern. In fact, the MAG-nonreactive patients were a heterogeneous group, both electrodiagnostically and clinically. This study supports the concept that MAG-reactive polyneuropathy is demyelinating in type, and is caused by the activity of the IgM M-protein directed at an antigen in the myelin sheath.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Demyelinating Diseases / diagnosis
  • Demyelinating Diseases / etiology
  • Electrodiagnosis*
  • Female
  • Humans
  • Hypergammaglobulinemia / complications*
  • Immunoglobulin M*
  • Male
  • Middle Aged
  • Myelin Proteins / immunology*
  • Myelin-Associated Glycoprotein
  • Neural Conduction / physiology
  • Peripheral Nervous System Diseases / diagnosis*
  • Peripheral Nervous System Diseases / etiology


  • Immunoglobulin M
  • Myelin Proteins
  • Myelin-Associated Glycoprotein