Disease Directory Thrombotic Thrombocytopenic Purpura
Blood

Thrombotic Thrombocytopenic Purpura

Also known as: TTP, ADAMTS13 deficiency, Moschcowitz disease

Prevalence

2-6 per million per year for acquired TTP

Onset

Any age; acquired form peaks in young adults; congenital form presents in infancy or childhood

Type

Acquired (immune-mediated) or congenital (Upshaw-Schulman syndrome)

Gene

ADAMTS13

About Thrombotic Thrombocytopenic Purpura

Thrombotic thrombocytopenic purpura is a life-threatening thrombotic microangiopathy caused by severe deficiency of the metalloprotease ADAMTS13, which normally cleaves ultra-large von Willebrand factor multimers; in acquired TTP this deficiency results from autoantibodies against ADAMTS13, while congenital TTP (Upshaw-Schulman syndrome) is caused by biallelic ADAMTS13 mutations. Unopposed ultra-large VWF multimers promote widespread platelet microthrombi in the microcirculation, causing thrombocytopenia, microangiopathic hemolytic anemia, and ischemic organ injury. Without prompt treatment with therapeutic plasma exchange, mortality approaches 90%.

Common Clinical Features

Thrombocytopenia with platelet counts often below 20,000/uL Microangiopathic hemolytic anemia with schistocytes on peripheral smear Fluctuating neurological symptoms including confusion, headache, and seizures Fever Renal impairment with elevated creatinine Fatigue and pallor from hemolysis Elevated LDH and indirect bilirubin Cardiac involvement including troponin elevation in severe cases

Clinical Trial Eligibility Tips

What to know before applying to Thrombotic Thrombocytopenic Purpura trials.

ADAMTS13 activity level below 10% with a detectable inhibitor or anti-ADAMTS13 IgG confirms acquired TTP and is required for most immunotherapy and novel agent trials; bring your acute episode laboratory results.

Caplacizumab use during acute episode and number of prior acute TTP episodes (relapses) are important eligibility variables for trials of rituximab combinations and novel immunosuppressants.

Congenital TTP (Upshaw-Schulman syndrome) patients with confirmed ADAMTS13 mutations may qualify for separate recombinant ADAMTS13 replacement trials distinct from acquired TTP studies.

Patient Resources

Patient Organization

TTP Alliance

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Natural History Registry

Oklahoma TTP Registry

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Orphanet

European reference resource for rare diseases (ORPHA:54057)

View on Orphanet ↗

NORD

National Organization for Rare Disorders

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Find recruiting Thrombotic Thrombocytopenic Purpura trials

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