The largest subgroup of IgG4-AID consists of anti-neuronal IgG4-AID (3), that include muscle-specific kinase (MuSK) myasthenia gravis (MG), leucine-rich glioma inactivated protein- 1 (LGI1)- and contactin-associated protein-like 2 (Caspr2)- encephalitis and autoimmune nodo-/paranodopathies with autoantibodies against contactin 1 (CNTN1)/contactin-associated protein-like 1 (Caspr1) or neurofascin-155 (NF155) (3). The gene discussed is LGI1; the disease is viral encephalitis.