CD59 marker deficiency leads to which of the following disease?

Ans. a. Paroxysmal nocturnal hemoglobinuria (PNH)Ref: Robbins and Cotran Pathologic Basis of Disease 9th Ed; Page No-642Paroxysmal Nocturnal HemoglobinuriaIncreases complement-mediated intravascular RBC lysis (impaired synthesis of GPI anchor for decay-accelerating factor that protects RBC membrane from complement).Acquired mutation in a hematopoietic stem cell.Increases incidence of acute leukemias.Patients may report red or pink urine (from hemoglobinuria).Associated with aplastic anemia.Triad: Coombs [?] hemolytic anemia, pancytopenia, and venous thrombosis.Labs: CD55/59 [?] RBCs on flow cytometry.PNH blood cells are deficient in three GPI-linked proteins that regulate complement activity:Decay accelerating factor, or CD55;Membrane inhibitor of reactive lysis, or CD59; andC8 binding protein.The most important is CD59, a potent inhibitor of C3 convertase that prevents the spontaneous activation of the alternative complement pathwayTreatment: Eculizumab (terminal complement inhibitor).