Children and adults with thrombotic thrombocytopenic purpura associated with severe, acquired Adamts13 deficiency: comparison of incidence, demographic and clinical features.
BACKGROUND
Thrombotic thrombocytopenic purpura (TTP) associated with severe, acquired ADAMTS13 deficiency is uncommonly reported in children. The incidence, demographic, and clinical features of these children, compared to adults, have not been described.


PROCEDURES
This study focused on children (<18 years old) and adults with TTP associated with severe, acquired ADAMTS13 deficiency, defined as activity <10%. The incidence rates for TTP in children and adults were calculated from patients enrolled in the Oklahoma TTP-HUS (Hemolytic-Uremic syndrome) Registry, 1996-2012. To describe demographic and clinical features, children with TTP were also identified from a systematic review of published reports and from samples sent to a reference laboratory for analysis of ADAMTS13.


RESULTS
The standardized annual incidence rate of TTP in children was 0.09 × 10(6) children per year, 3% of the incidence rate among adults (2.88 × 10(6) adults per year). Among the 79 children who were identified (one from the Oklahoma Registry, 55 from published reports, 23 from the reference laboratory), TTP appeared to be more common among females, similar to the relative increased frequency of women among adults with TTP, and more common in older children. Clinical data were available on 52 children; the frequency of severe renal failure, relapse, treatment with rituximab, and systemic lupus erythematosus in these children was similar to adults with TTP.


CONCLUSIONS
TTP associated with severe, acquired ADAMTS13 deficiency is uncommon in children. The demographic and clinical features of these children are similar to the features of adults with TTP.
['Reese|Jessica A|JA|', 'Muthurajah|Darrshini S|DS|', 'Kremer Hovinga|Johanna A|JA|', 'Vesely|Sara K|SK|', 'Terrell|Deirdra R|DR|', 'George|James N|JN|']
D051722:ADAM Proteins D000071120:ADAMTS13 Protein D000293:Adolescent D000328:Adult D000367:Age Factors D058846:Antibodies, Monoclonal, Murine-Derived D002648:Child D002675:Child, Preschool D005260:Female D006801:Humans D007155:Immunologic Factors D015994:Incidence D007564:Japan D008180:Lupus Erythematosus, Systemic D008297:Male D011697:Purpura, Thrombotic Thrombocytopenic D012008:Recurrence D012042:Registries D051437:Renal Insufficiency D012189:Retrospective Studies D000069283:Rituximab D012737:Sex Factors
children thrombotic thrombocytopenic purpura incidence TTP disparities