About Factor XIII Deficiency
Factor XIII deficiency is an ultra-rare congenital bleeding disorder caused by biallelic mutations in F13A1 (encoding the FXIII-A catalytic subunit) or F13B (encoding the carrier FXIII-B subunit), resulting in deficiency of the transglutaminase that cross-links fibrin polymers to form a mechanically stable clot. Because standard coagulation tests (PT, aPTT) are normal in FXIII deficiency, diagnosis is often delayed, and the condition is characterized by a distinctive pattern of delayed bleeding occurring hours to days after injury once primary hemostasis is established but clot stability is compromised. Severe FXIII deficiency carries high risks of intracranial hemorrhage, recurrent miscarriage, and impaired wound healing.
Common Clinical Features
Clinical Trial Eligibility Tips
What to know before applying to Factor XIII Deficiency trials.
Factor XIII activity level (chromogenic or functional assay) is essential for diagnosis confirmation and trial eligibility; severe deficiency is defined as FXIII activity below 1-5%, and activity levels correlate with bleeding phenotype.
Genetic mutation identification in F13A1 or F13B helps classify type (A subunit vs B subunit deficiency), with type A being more common and clinically severe; bring genetic test results to screening appointments.
Prophylactic FXIII replacement therapy history, including product used, dose, frequency, and any breakthrough bleeding events, is required documentation for trials evaluating recombinant FXIII or novel long-acting replacement products.
Patient Resources
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