Acute episodes of TTP are marked by a severe deficiency of a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS13), with the standard of care initial diagnosis being defined by enzymatic activity of less than 10% of normal ADAMTS13 in countries where this assay is available [2,3]. This evidence concerns the gene ADAMTS13 and thrombotic thrombocytopenic purpura.