Paroxysmal nocturnal hemoglobulinuria

Definition

PNH is a clonal disorder of hematopoietic stem cells with faulty glycolipid anchors leading to membrane protein dysfunction. In particular without the anchor proteins can not migrate out of the intracellular Golgi apparatus. Approximately 15 proteins have been found to date affected by said mutation they include: complement defense proteins, immunologic proteins, enzymes, receptors, and granulocyte proteins of unknown function. Both normal and abnormal erythrocytes, granulocytes, monocytes, and platelets can be found at any one time. The faulty gene expression has been localized to the X chromosome. Clinical presentation includes haemolytic anemia, relative and absolute bone marrow failure, thrombophilia (particularly Budd-Chiari syndrome), dysphagia, impotence, severe low back pain, and fatigue. Diagnosis is best with flow cytometric analysis for membrane protein deficiencies especially CD59 and CD55 are recommended.