Paroxysmal Nocturnal Hemoglobinuria
National Organization for Rare Disorders, Inc.
It is possible that the main title of the report Paroxysmal Nocturnal Hemoglobinuria is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.
Paroxysmal nocturnal hemoglobinuria (PNH) is a rare disorder in which red blood cells break apart prematurely. It is an acquired hematopoietic stem cell disorder. Hematopoietic stem cells are created in the bone marrow, the spongy center of the long bones of the body. These cells grow and eventually develop into red blood cells, white blood cells and platelets. Some hematopoietic stem cells in individuals with PNH are defective and consequently produce defective blood cells. These defective red blood cells of PNH are extremely susceptible to premature destruction by a particular part of a person's own immune system called the complement system.
The destruction of red blood cells (hemolysis) by complement leads to episodes of hemoglobin in the urine (hemoglobinuria). Hemoglobin is the red, iron-rich, oxygen-containing pigment of the blood. Individuals with hemoglobinuria may exhibit dark-colored or blood colored urine. This finding is most prominent in the morning, after the urine has concentrated overnight during sleep. However, hemolysis in individuals with PNH is a constant process, it does not occur only at night. Hemoglobin in the urine may not always be visible to the eye.
In addition to hemolysis, individuals with PNH are also susceptible to developing repeated, potentially life-threatening blood clots (thromboses). Affected individuals also have some degree of underlying bone marrow dysfunction. Severe bone marrow dysfunction results in low levels of red and white blood cells and platelets (pancytopenia). The specific symptoms of PNH vary greatly from one person to another and affected individuals usually do not exhibit all of the symptoms associated with the disorder.
Aplastic Anemia & MDS International Foundation, Inc.
100 Park Avenue, Suite 108
Rockville, MD 20850
NIH/National Heart, Lung and Blood Institute ~ Hematology Branch
10 Center Dr, Building 10-CRC
Bethesda, MD 20892-1202
PNH Support Group
Genetic and Rare Diseases (GARD) Information Center
PO Box 8126
Gaithersburg, MD 20898-8126
PNH Research and Support Foundation
PO Box 10983
Rockville, MD 20849
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It is possible that the title of this topic is not the name you selected. Please check the Synonyms listing to find the alternate name(s) and Disorder Subdivision(s) covered by this report
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Last Updated: 1/28/2014
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