label: Paroxysmal Nocturnal Hemoglobinuria
label_lc: paroxysmal nocturnal hemoglobinuria
description: A rare acquired hematologic disorder characterized by hemolytic anemia, dark-colored urine due to the release of hemoglobin in the blood, and thrombosis. The episodes of hemolysis tend to occur at night. It is caused by a somatic mutation in the glycosylphosphatidylinositol biosynthesis gene.