Eculizumab (Soliris®, Alexion Pharmaceuticals, Inc., New Haven, CT, USA), a humanized monoclonal antibody that inhibits C5a, C5b and C5b-9 formation by binding to C5, is the first and only approved treatment for patients with aHUS [5, 6]. The gene discussed is C5; the disease is atypical hemolytic-uremic syndrome.