Therapy of Hereditary TTP with ADAMTS13 Deficiency - A Case Report and Review of the Literature.

Deficiency of von Willebrand factor (VWF) cleaving protease ADAMTS13 is associated with the development of thrombotic thrombocytopenic purpura (TTP). ADAMTS13 gene mutations cause the hereditary TTP. We describe a patient with relapsing TTP, who failed to achieve sustained remission despite therapies with plasma exchange, steroids, vincristine and ATG. There was lower ADAMTS13 inhibitor titre and lower activity of ADAMTS13 enzyma in the patient’s plasma. Sequence analysis of DNA amplified by polymerase chain reaction showed that the patient was homozygous for two novel missense mutations in TSP1 repeated motif domain of ADAMTS13. In both mutations cytisine were subtituded by thymine. One was a Serine to Leucine substitution in NT 3152, exon21(codon S903L); the other is a Arginine to a Tryptophan substitution in NT3727, exon 25(codon R1094W), while both parents were heterozygous for the same mutation. The patient was dialogue as hereditary TTP. The patient receives 600 to 800 ml plasma transfusion every 3 weeks and now she is very well and works again.

Hereditary TTP with ADAMTS13 deficiency could be treated with the infusion of only a few units of plasma, without plasma exchange. Gene therapy may eventually cure hereditary TTP.