A range of laboratory tests was performed to investigate the following antibodies: the paraneoplastic (anti-Hu, anti-Ri, anti-Yo, anti-CV2, anti-Amphiphysin, anti-Ma1, anti-Ma2), the infectious (including syphilis and HIV) and the autoimmune (including anti-nuclear antibodies, antibodies against extractable nuclear antigens, anti-double- and single-stranded DNA; anti-neutrophil cytoplasmic antibodies, anticardiolipin antibodies, anti-cyclic citrullinated peptide antibodies and anti-aquaporin-4 (AQP4)), all proved negative. This evidence concerns the gene AQP4 and syphilis.