These patients were previously classified as having “aHUS”, clinically defined as thrombocytopenia and microangiopathic hemolysis (with ADAMTS13 activity of >5% and a negative stool test for Shiga-toxin-producing infection) and one of the following: neurological symptoms, renal impairment, or gastrointestinal symptoms [9]. The gene discussed is ADAMTS13; the disease is Thrombocytopenia.