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.
Kaku
D A
DA
Department of Neurology, Louisiana State University School of Medicine, New Orleans 70121.
England
J D
JD
Sumner
A J
AJ
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