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Paroxysmal Nocturnal Hemoglobinuria (PNH)
Alternate Names : PNH
DefinitionParoxysmal nocturnal hemoglobinuria is a rare, acquired disorder of red blood cells in which an abnormal cell surface molecule leads to premature destruction of the cells. This destruction is intermittent (paroxysmal).
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Overview, Causes, & Risk Factors
PNH is caused by a defect in the formation of a red cell surface protein anchor, called GP1. As a result of the lack of this surface protein anchor, a number of surface proteins are unable to remain tethered to the cell surface. This includes the protein CD55, or Decay Accelerating Factor (DAF).
The result of the loss of these cell surface proteins is an enhanced sensitivity to complement-mediated cell destruction. (Complement is a substance produced by the immune system.) The disease can affect people of any age.
Red blood cell, white blood cell, and platelet counts may be low. Urine may be intermittently red or brown, signifying the breakdown of red blood cells with release of hemoglobin into the circulation and then the urine.
Blood clots may form in some people. The disease may arise in relation to aplastic anemia, and may progress to acute myelogenous leukemia. Risk factors, except for prior aplastic anemia, are not known.
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• Definition
• Overview, Causes, & Risk Factors
• Symptoms & Signs
• Prevention
• Diagnosis & Tests
• Treatment
• Prognosis
• Complications
• Calling Your Health Care Provider
• Pictures & Images
Topics that might be of interest to you Diseases & Conditions
• Acute Myelogenous Leukemia (AML) - Adult
• Blood Clots
• Hemolytic Anemia
• Iron Deficiency Anemia
Tests & Exams
• CBC
• Complement
• Ham's (Acid Hemolysin) Test
• Hemoglobin
• Platelet Count
• RBC Count
• Serum Hemoglobin
• Sugar-Water Hemolysis Test
• Urinalysis
• WBC Count
Other Topics
• Urine - Bloody
Review Date : 10/13/2003
Reviewed By : Corey Cutler, M.D., M.P.H., F.R.C.P.C, Department of Medical Oncology, Dana-Farber Cancer Institute; Instructor in Medicine, Harvard University, Boston, MA. Review provided by VeriMed Healthcare Network.
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