Atypical hemolytic uremic syndrome

Abstract Atypical hemolytic uremic syndrome (aHUS) is a thrombotic microangiopathy (TMA) characterized by microangiopathic hemolytic anemia, thrombocytopenia, and acute renal failure. Most cases of aHUS are caused by uncontrolled complement activation due to genetic mutations in the alternative pathway of complement. More recently, mutations in the gene of coagulation system have also been identified in patients with aHUS. In Japan, the recent studies of aHUS have identified the unique genetic characteristics in our country and enabled us to revise the diagnostic criteria. In this article, we review the classification of TMAs and describe the pathophysiology, diagnosis, and management of aHUS. We also highlight current progress in clinical and basic research of the patients with aHUS in Japan