What is Paroxysmal nocturnal hemoglobinuria (PNH)
Paroxysmal nocturnal hemoglobinuria (PNH) is a rare disease in which red blood cells break down earlier than normal. 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 substances in the blood called complement. As a result, red blood cells break down too early. The red 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 be associated with aplastic anemia, myelodysplastic syndrome, or acute myelogenous leukemia. Risk factors, except for prior aplastic anemia, are not known. The outcome varies. Most people survive for more than 10 years after their diagnosis. Death can result from complications such as blood clot formation (thrombosis) or bleeding. In rare cases, the abnormal cells may decrease over time.
Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired disorder that leads to the premature death and impaired production of blood cells. It can occur at any age, but is usually diagnosed in young adulthood. People with PNH have recurring episodes of symptoms due to hemolysis, which may be triggered by stresses on the body such as infections or physical exertion. This results in a deficiency of various types of blood cells and can cause signs and symptoms such as fatigue, weakness, abnormally pale skin (pallor), shortness of breath, and an increased heart rate. People with PNH may also be prone to infections and abnormal blood clotting (thrombosis) or hemorrhage, and are at increased risk of developing leukemia. It is caused by acquired, rather than inherited, mutations in the PIGA gene; the condition is not passed down to children of affected individuals. Sometimes, people who have been treated for aplastic anemia may develop PNH. The treatment of PNH is largely based on symptoms; stem cell transplantation is typically reserved for severe cases of PNH with aplastic anemia or those whose develop leukemia.
This information is provided by the National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).
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