However, reports of some patients with a clinical diagnosis of TTP without severe ADAMTS-13 deficiency [36], and the presence of a few individuals with severe ADAMTS-13 deficiency who either do not develop TTP or do so only later in life [37,38], suggest that other molecules (as co-factors) may be involved in the pathogenesis of TTP. Here, ADAMTS13 is linked to thrombotic thrombocytopenic purpura.