In the context of acquired BMF syndromes, paroxysmal nocturnal hemoglobinuria (PNH) is a clonal disease caused by a somatic mutation in the PIGA-gene resulting in the deficiency of GPI-anchored proteins (such as CD55 and CD59) and leads to erythrocytes unable to control complement activation (15–18). This evidence concerns the gene CD55 and paroxysmal nocturnal hemoglobinuria.