<prompt> Which of the following is the only hemolytic anaemia caused by acquired intrinsic defect in the cell membrane:Sickle cell anaemiaThalassemiaPNHNone of the above  <response>: PNH is the only hemolytic anemia caused by an acquired intrinsic defect in the cell membrane. The stem cells of the bone marrow acquire mutations in Phosphatidyl inositol glycan A PIGA gene. The triad of hemolysis, pancytopenia and thrombosis is unique to PNH. Thrombosis is the leading cause of disease related death in PNH. 