The discovery of PNS-specific SGPG glycolipid however, that all anti-MAG-positive patients immunoreact with, has strengthened the view that glycolipids, along with glycoproteins, may be the primary antigenic targets.9,10,16,26,27 The following factors provide convincing evidence that these antibodies are causally related to the neuropathy:. This evidence concerns the gene MAG and neuropathy.