Expanding spectrum of GAD autoantibody associated neurological diseases

• Published in: Pathology Vol. 45; pp. S45 - S46
• Main Author: Tan, K. Meng
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 2013
• ISSN: 0031-3025; 1465-3931
• DOI: 10.1097/01.PAT.0000426833.56694.e1

Glutamic acid decar boxylase (GAD) autoantibodies were first recognised in association with stiff man syndrome, and remain extremely helpful in establishing this diagnosis. Subsequently, these autoantibodies have been identified in patients with autoimmune forms of encephalopathy, epilepsy, brainstem dysfunction and cer-ebellar ataxia. Similar clinical heterogeneity is seen with several other neuron-specific autoantibody markers of autoimmune, often paraneoplastic, neurological disease; however, GAD autoantibod-ies are not predictive of an underlying neoplasm. While GAD is abundant within the central nervous system, the contribution of GAD autoantibodies to the pathogenesis of autoimmune neurological disease remains unclear. Reports of a tight association with juvenile neuronal ceroid lipofuscinosis, a genetically determined neurodegenerative disease, raise the possibility that GAD autoantibodies can occur as an epiphenomenon in other, non-autoimmune, disorders. Considering the association with non-neurological autoimmune disease, including diabetes mellitus and thyroiditis, and the relatively high prevalence of GAD autoantibodies in healthy controls, positive assays in patients with unusual neurological presentations should be interpreted with great caution and within the broader clinical context.