A Study to Learn More About the Treatment of People With Congenital Thrombotic Thrombocytopenic Purpura (cTTP) Who Received Recombinant ADAMTS13 (rADAMTS13) as Part of the Early Access Program

Congenital thrombotic thrombocytopenic purpura (cTTP) is a rare blood disorder that some people are born with. It is caused by inherited changes in the ADAMTS13 gene that reduce the body's ability to produce the ADAMTS13 enzyme. ADAMTS13 normally cleaves ultra-large multimers of a protein called von Willebrand factor (VWF). In cTTP, low ADAMTS13 activity allows these ultra-large VWF multimers to build up and promote blood clot formation in small blood vessels. These clots can restrict blood flow to vital organs and lead to serious complications. Recombinant ADAMTS13 (rADAMTS13) is a manufactured form of human ADAMTS13 designed to replace the missing enzyme and restore ADAMTS13 activity. This study aims to describe the impact of cTTP on participants before and after treatment with rADAMTS13. It will also evaluate participants' health outcomes after treatment and describe treatment patterns before and after rADAMTS13, including whether treatment was used to prevent or treat TTP episodes, how often it was given, the amount received, and others. In addition, the study will describe pregnancies and outcomes for the mother and baby before and during treatment with rADAMTS13. Only data already available in the medical records of the people who received rADAMTS13 through Takeda's early access program (EAP) for cTTP will be collected and reviewed in this study.

Inclusion criteria for the rADAMTS13 EAP are: * Participants of any age can participate who have a confirmed diagnosis of severe congenital ADAMTS13 deficiency or cTTP. * Participants must be on preventative or prophylactic treatment for cTTP or must have had at least one TTP event in the past. * Participants must have no other treatment options available (this includes other clinical studies for cTTP). The inclusion criteria for this retrospective chart review are: * Pediatric and adult participants (no age restrictions) with cTTP, treated with rADAMTS13 via the EAP, who received at least two administrations of rADAMTS13 and who have provided consent (or the legal guardians) to participate in this retrospective chart review. * As per local regulations, evidence of a personally signed (or signed by a legally acceptable representative) and dated informed consent form/informed assent form (ICF/IAF) indicating that the participant (or their legal guardian) has been informed of all pertinent aspects of the retrospective chart review or an approval to process data without informed consent granted by an institutional review board/independent ethics committee (IRB/IEC)) Participants included in the EAP who were/are transitioned to the commercially available product will have their data abstracted for the duration of their participation in the EAP as well as when they received the commercially available product until the end of chart abstraction. There are no additional exclusion criteria for this chart review.