This is a UK (United Kingdom) based registry, involving all sites treating newly presenting Thrombotic Thrombocytopenic Purpura (TTP). From this registry, important epidemiological data will be obtained. Admission and remission samples will be collected. DNA will be collected and analysed from patients wishing to participate to determine if any link exists between mutations/polymorphisms and the risk of TTP. As part of NHS commissioning, we will be undertaking long term follow up, to understand the impact of acute TTP on morbidity and mortality.

The UK TTP registry started in January 2009, following 3 years MRC funding, involving UK collaboration from all sites treating TTP patients. It has resulted in a cohort of data and samples from UK TTP cases. The registry promotes a collaborative approach with all UK patients and physicians involved with this life threatening disorder. The UK TTP registry has been used to provide information for highly specialist commissioning via NHS England and moving forward will be required to provide data relevant to the UK TTP Group and commissioners.

University College London (UCL) Haemostasis Research Unit (HRU) will collect and collate the data and help administrate for those sites participating in the registry. However, ADAMTS13 assays will no longer be subsidised. For those sites undertaking local assays, a record of cases will be shared centrally. The UK TTP registry will be part of the UK TTP Group.

Inclusion Criteria:

• Patients with a clinical diagnosis of TTP, defined by thrombocytopenia, MAHA which may be associated with clinical evidence of organ compromise.Confirmed by severely reduced ADAMTS13 levels and/or a positive antibody screen.
• No age restriction.
• Consent for addition to the Registry and collection/storage of admission information once in remission.
• Consent to collect, analyse and store EDTA sample once in remission.
• Consent to store samples once in remission (sample taken as part of standard care).
• For sites undertaking ADAMTS13 analysis, consent to send admission and remission samples for analysis relating to TTP.
• Follow up laboratory and clinical data at least yearly to identify any changes.

Exclusion Criteria:

• Patients with cancer or transplant associated MAHA will not be included.
• Patients not wishing to be involved with the registry.

Patients presenting with an acute episode of Thrombotic Thrombocytopenic Purpura (TTP) will be asked to consent for the registry once in remission. However, for those sites undertaking ADAMTS13 analysis, consent for admission and remission samples for TTP cases will be requested. A screening log of all cases analysed will be kept by sites and forwarded at 3 monthly intervals. This will help identify other non-TTP causes for ADAMTS13 analysis.