(PNH) a type of acquired haemolytic anaemia that results from an abnormality of the red blood cell membrane. It is due to a defect in the formation of glycosylphosphatidylinositol (GPI), whose role is to anchor proteins to the lipid framework of the membrane. This leads to increased complement-mediated destruction of red blood cells, which results in the release of haemoglobin in the circulation and then in the urine, giving the latter a reddish colour. Some patients may develop blood clots.
Subjects: Medicine and Health — Chemistry.