Since MUC4 mutation can increase the risk of thrombosis in PNH patients and given the important role of MUC4 in antiadhesion, we hypothesised that the loss of MUC4 expression may promote the thrombotic phenotype in PNH patients by increasing the deposition of terminal complement on the cell surface. The gene discussed is MUC4; the disease is paroxysmal nocturnal hemoglobinuria.