Certainly, GAD Ab can be detected in the serum of 0.4%–1.7% of healthy subjects [16,84,86,87], in the serum of 5% of patients with neurological disorders of other etiology [16], and in the serum of 80% of newly diagnosed patients with T1DM [25], highlighting the importance to interpret the results of serum testing in the light of neurological presentation and alternative etiologies, demanding CSF testing in ambiguous cases. The gene discussed is GAD1; the disease is type 1 diabetes mellitus.