Anti-GAD

Anti-glutamic acid decarboxylase (GAD) antibodies have been associated with type 1 diabetes mellitus and a large variety of neurological conditions, including epilepsy (1).

GAD antibodies are also associated with other conditions such as Stiff Man syndrome.

The background frequency of anti-GAD antibodies in the general population has been assessed to be around 0.4-1% (2)

Reference:

• Saiz A, Blanco Y, Sabater L, et al. Spectrum of neurological syndromes associated with glutamic acid decarboxylase antibodies: diagnostic clues for this association. Brain 2008;131:2553-63
• Batstra MR, van Driel A, Petersen JS, et al. Glutamic acid decarboxylase antibodies in screening for autoimmune diabetes: influence of comorbidity, age, and sex on specificity and threshold values. Clin Chem 1999;45:2269-72.