Which of the following is the only hemolytic anaemia caused by acquired intrinsic defect in the cell membrane:

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.