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Paroxysmal nocturnal hemoglobinuria (PNH) - Overview

Alternative Names

PNH

Definition of Paroxysmal nocturnal hemoglobinuria (PNH):

Paroxysmal nocturnal hemoglobinuria is a rare disease in which red blood cells break down earlier than normal.

Causes, incidence, and risk factors:

Persons with this disease have blood cells that are missing a gene called PIG-A. This gene allows a substance called glycosyl-phosphatidylinositol (GPI) to help certain proteins stick to cells.

Without PIG-A, important proteins cannot connect to the cell surface and protect the cell from destructive substances in the blood. As a result, blood cells break down too early. The cells leak hemoglobin into the blood, which can pass into the urine. This can happen at any time, but is more likely to occur during the night or early morning.

The disease can affect people of any age. It may lead to aplastic anemia , myelodysplastic syndrome, or acute myelogenous leukemia.

Risk factors, except for prior aplastic anemia, are not known.

Blood cells

Reviewed last on: 11/10/2008
David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and James R. Mason, MD, Oncologist, Director, Blood and Marrow Transplantation Program and Stem Cell Processing Lab, Scripps Clinic, Torrey Pines, California. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

References

US Food and Drug Administration. FDA Approves First-of-its-Kind Drug to Treat Rare Blood Disorder. Rockville, MD: National Press Office; March 16, 2007. Release P07-47.

Schwartz RS. Autoimmune and intravascular hemolytic anemias. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 164.

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