ADAMTS13 and atypical hemolytic-uremic syndrome: In adults, the causes of TMA include Shiga toxin-related hemolytic (STEC) uremic syndrome (HUS), a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS13)-acquired deficiency and atypical HUS (aHUS) secondary to complement alternative pathway dysregulation.