Anti-glutamic acid decarboxylase antibody (GAD) syndromes may have more aggressive disease course in African Americans and early onset of presentation compare to Caucasians group

Abstract

Anti-Glutamic acid decarboxylase antibodies (GAD) are increasingly diagnosed in the clinic and this antibody related syndromes can manifest commonly as autoimmune encephalitis, Stiff person syndrome and cerebellar ataxia. However, it is unclear if the race has role in age of incidence, presentation and severity of symptoms of anti-GAD associated conditions. In our cohort of 40 patients who were anti-GAD positive, we observed that the age at which the anti-GAD titers turned out to be positive was significantly lower in African Americans (AA) compared to Caucasians (Cau) irrespective of the type of conditions. However, the age at symptoms onset didn't differ significantly different between these groups. Furthermore, AA anti-GAD positive patients had seizures as their initial presentation that was significantly higher in incidence compared to Cau indicating that AA have more aggressive form of autoimmune phenomenon for reasons unknown. Future studies to explore the variations in autoimmune process and their phenotypes may aid in understanding anti-GAD syndromes differently between these racial groups. Keywords: Stiff person syndrome, Limbic encephalitis, Autoimmune epilepsy, Refractory seizure