CD55 and paroxysmal nocturnal hemoglobinuria: PNH can be caused by an acquired mutation in the phosphatidylinositol-N-acetylglucosaminyltransferase-subunit-A gene (PIG-A) that leads to the deficiency of cellular anchors for complement inhibitor proteins cluster of differentiation CD55 (decay accelerating factor, DAF, which stabilizes C3 and C5 convertase) and CD59 (membrane inhibitor of reactive lysis, MIRL, which inhibits membrane attack complex formation) [70,75].