The first anticomplement drug approved by the US Food and Drug Administration (FDA) and the European Medicines Agency in 2007 for the treatment of paroxysmal nocturnal hemoglobinuria (PNH) [79] and later for Atypical Hemolytic Uremic Syndrome (aHUS), Generalized Myasthenia Gravis [80], and Neuromyelitis Optica Spectrum disorders [81] was the long-acting humanized anti-C5 monoclonal antibody (mAb) Eculizumab (Soliris®, Alexion Pharmaceuticals, Boston, MA, USA). The gene discussed is C5; the disease is atypical hemolytic-uremic syndrome.