Of our 11 patients with overlapping autoimmune syndromes, one patient developed autoimmune GFAP-A 1 year after the diagnosis of AQP4 antibody-related neuromyelitis optica; one patient was found to be positive for GFAP antibodies a few months after the diagnosis of MOG-associated disease; and the remaining nine patients showed other autoimmune antibodies contemporaneous with positivity for GFAP antibodies, challenging the diagnosis. The gene discussed is GFAP; the disease is neuromyelitis optica.