Although a low number of cases have been reported, a study from the French National Reference Center for Paraneoplastic Neurological Syndromes (Vogrig et al., 2019a) discovered a 112% increase in the detection of anti-Ma2 Abs since the generalization of ICIs in clinical practice, whereas the increase of other onconeural Ab detection (anti-GAD, anti-Hu, anti-Yo, anti-LGI1, anti-NMDA, anti-CASPR2, anti-GABABr, and anti-AMPAr) was significantly lower (30%–50%), suggesting a particularly firm association between ICIs and anti-Ma2 encephalitis. The gene discussed is GAD1; the disease is viral encephalitis.