The other five did not show MG and presented heterogeneous clinical manifestations: one had neuromyelitis optica with concurrent anti-aquaporin-4 (AQP4) immunoglobulin G serum positivity, so no anti-Hu related PNS; four had sensory or painful neuropathy preceded by episodic vertigo in two cases; one of them later developed seizures, encephalitis and autonomic disturbances with constipation and fixed dilated pupils. This evidence concerns the gene AQP4 and viral encephalitis.