The authors reported the neurological disease spectrum associated with 
autoantibodies against minor gangliosides GM1b and GalNAc-GD1a. IgG and IgM 
antibody reactivity against gangliosides GM1, GM2, GM1b, GD1a, GalNAc-GD1a and 
GQ1b was investigated in sera from 7000 consecutive patients who had various 
neurological conditions. The clinical diagnoses for 456 anti-GM1b-positive 
patients were Guillain-Barré syndrome (GBS, 71%), atypical GBS with preserved 
deep tendon reflexes (12%), Fisher syndrome (10%), Bickerstaff's brainstem 
encephalitis (2%), ataxic GBS (2%) and acute ophthalmoparesis (1%). For 193 
anti-GalNAc-GD1a-positive patients, the diagnoses were GBS (70%), atypical GBS 
(16%), Fisher syndrome (10%) and Bickerstaff's brainstem encephalitis (3%). Of 
the patients with GBS or atypical GBS, 28% of 381 anti-GM1b-positive and 31% of 
166 anti-GalNAc-GD1a-positive patients had neither anti-GM1 nor anti-GD1a 
antibodies. Of those patients with Fisher syndrome, Bickerstaff's brainstem 
encephalitis, ataxic GBS or acute ophthalmoparesis, 33% of 67 
anti-GM1b-positive, and 52% of 25 anti-GalNAc-GD1a-positive patients had no 
anti-GQ1b antibodies. Autoantibodies against GM1b and GalNAc-GD1a are associated 
with GBS, Fisher syndrome and related conditions. These antibodies should 
provide useful serological markers for identifying patients who have atypical 
GBS with preserved deep tendon reflexes, ataxic GBS, Bickerstaff's brainstem 
encephalitis or acute ophthalmoparesis, especially for those who have no 
antibodies to GM1, GD1a or GQ1b. A method to prepare GM1b was developed.