Multiple etiologies of TMA have been described including autoantibodies against ADAMTS13 (causing thrombotic thrombocytopenic purpura), infections [most commonly with Shiga toxin producing E. coli O157 producing hemolytic uremia syndrome (HUS)], mutations of the complement regulatory pathways (producing atypical HUS), and drug-induced TMA (George and Nester, 2014; Reese et al., 2015). The gene discussed is ADAMTS13; the disease is hemolytic-uremic syndrome.