A young man was reported to have several episodes of TTP with undetectable ADAMTS13 activity caused by two novel mutations in the ADAMTS13 gene: a single nucleotide deletion in exon 17 (c.2042 delA) causing a frameshift (K681C fs X16) and an additional missense mutation in exon 25 (c.3368G > A) resulting in p.R1123H [32]. Here, ADAMTS13 is linked to thrombotic thrombocytopenic purpura.