Distal accentuation of conduction slowing in polyneuropathy associated with antibodies to myelin-associated glycoprotein and sulphated glucuronyl paragloboside.
In four patients with a chronic, demyelinating polyneuropathy associated with monoclonal IgM antibodies to myelin-associated glycoprotein (MAG) and sulphated glucuronyl paragloboside (SGPG), we have observed a marked prolongation of distal motor latencies disproportionate to proximal segment-conduction velocities, in nearly all nerves studied. Distal accentuation of conduction slowing distinguished these patients from those with Charcot-Marie-Tooth polyneuropathy type 1A, chronic inflammatory polyneuropathy, and from controls, as demonstrated by regression of distal motor latency on proximal conduction velocity. Sixteen of 21 nerves (76%) studied in the patients with anti-MAG/SGPG polyneuropathy had a terminal latency index of < or = 0.25 versus 11 of 195 nerves (6%) of Charcot-Marie-Tooth polyneuropathy type 1A patients, three of 49 nerves (6%) of patients with chronic inflammatory polyneuropathy and none of the controls (P = 0.0001). Recognition of this unique pattern of generalized, distally predominant conduction slowing in anti-MAG/SGPG polyneuropathy may be useful in clinically distinguishing this from other chronic demyelinating polyneuropathies, and in possibly providing insights into the pathophysiology of this disorder.
Department of Neurology, Louisiana State University School of Medicine, New Orleans 70121.
D A
DA
Kaku
J D
JD
England
A J
AJ
Sumner
D000368:Aged; D000906:Antibodies / Q000032:analysis*; D005260:Female; D005915:Globosides / Q000276:immunology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009046:Motor Neurons; D009185:Myelin Proteins / Q000276:immunology*; D009431:Neural Conduction; D010523:Peripheral Nervous System Diseases / Q000276:immunology* / Q000503:physiopathology*
D000906:Antibodies; D005915:Globosides; D009185:Myelin Proteins; C051917:sulfate-3-glucuronyl paragloboside