It was concluded that in SPS: a) there is marked intrathecal antibody response against neuronal GAD65 epitopes [18], indicating clonal B cell activation in the CNS; b) GABA level is reduced in the CSF indicative of impaired GABA synthesis; and c) only high anti-GAD65 antibody titers, confirmed with immunoblots, are highly specific for SPS. This evidence concerns the gene GAD2 and stiff-person syndrome.