Brain MRI with and without contrast for detecting MS or ADEM; CSF analysis for cell count, protein, glucose, OCBs, IgG index, and cytology; serum NMO IgG antibodies (anti-aquaporin-4 IgG); serum B12; methylmalonic acid; human immunodeficiency antibodies; thyroid function test; antiphospholipid antibodies, antinuclear antibodies, rheumatoid factor and anti-dsDNA (35). The gene discussed is AQP4; the disease is neuromyelitis optica.