Paroxysmal Nocturnal Hemoglobinuria (PNH)

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, chronic, and potentially life-threating blood disorder that occurs when unregulated complement activity causes the destruction of red blood cells (hemolysis) and the formation of life-threatening blood clots (thrombosis).
In PNH, the body’s stem cells acquire a gene mutation which results in the production of abnormal blood cells that lack two important surface proteins that act as a shield to protect the body from attack and destruction by complement. As a result, the complement protein C3 becomes overactivated in patients with PNH, which triggers two types of hemolysis at the same time: intravascular and extravascular hemolysis. This can result in severe anaemia and many other symptoms like kidney failure or abdominal pain.

Video by Apellis Pharmaceuticals