title: Multifocal motor neuropathy with high titers of anti-MAG antibodies.
abstract: Multifocal motor neuropathy (MMN) and anti-myelin-associated glycoprotein (anti-MAG)-associated neuropathy are clinically and electrophysiologically distinct entities. We describe a patient with characteristic features of both neuropathies, raising the possibility of an overlap syndrome. A 49-year-old patient reported a history of slowly progressive predominantly distal tetraparesis, with mild sensory deficits. Nerve conduction studies demonstrated persistent motor conduction blocks outside compression sites, typical of MMN. Laboratory findings revealed persistently high titers of anti-MAG immunoglobulin Mλ (IgMλ) paraprotein in the context of a monoclonal gammapathy of unknown significance. Skin biopsy of distal lower limb revealed IgM positive terminal nerve perineurium deposits. This case suggests that the distinction between subtypes of chronic inflammatory neuropathies may not be as clear as initially thought, and that the pattern of pathogenicity of anti-MAG antibodies may vary.
authors.affiliation: Department of Clinical Neurosciences, Division of Neurology, Geneva University Hospital, Geneva, Switzerland.
authors.forename: Claire
authors.initials: C
authors.lastname: Bridel
authors.forename: Judit
authors.initials: J
authors.lastname: Horvath
authors.forename: Mary
authors.initials: M
authors.lastname: Kurian
authors.forename: André
authors.initials: A
authors.lastname: Truffert
authors.forename: Andreas
authors.initials: A
authors.lastname: Steck
authors.forename: Patrice H
authors.initials: PH
authors.lastname: Lalive
mesh_terms: D001323:Autoantibodies / Q000097:blood*; D005260:Female; D006801:Humans; D007075:Immunoglobulin M / Q000378:metabolism; D007382:Intermediate Filaments / Q000378:metabolism; D008875:Middle Aged; D009186:Myelin Sheath / Q000378:metabolism / Q000473:pathology; D018992:Myelin-Associated Glycoprotein / Q000276:immunology*; D009431:Neural Conduction; D010265:Paraproteinemias / Q000097:blood* / Q000150:complications / Q000276:immunology; D011115:Polyneuropathies / Q000097:blood* / Q000150:complications / Q000276:immunology
chemical_list: D001323:Autoantibodies; D007075:Immunoglobulin M; D018992:Myelin-Associated Glycoprotein
keywords: anti-MAG neuropathy; immune-mediated peripheral neuropathy; multifocal motor neuropathies