RecruitingPhase 4NCT06481995
Blood
Factor XIII Deficiency
Also known as fibrin stabilizing factor deficiency, FXIII deficiency, Laki-Lorand factor 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 transglutami
ORPHA:331 ↗Gene F13A1Gene F13BPrevalence 1 in 1,000,000 to 1 in 5,000,000Onset Neonatal period; umbilical stump bleeding is often the first signAutosomal recessive
1
studies recruiting now
as of 7 Sept 2026
19
studies registered in total
as of 7 Sept 2026
1
countries with a recruiting site
as of 7 Sept 2026
1 Jul 2024
most recent study posted
among recruiting studies
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Showing the 1 most recently updated recruiting study, as recorded 7 Sept 2026. Live status on each study page.
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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
Umbilical cord stump bleeding in the neonatal period (pathognomonic sign)Delayed bleeding after injury, surgery, or dental proceduresRecurrent intracranial hemorrhageHabitual miscarriage in affected women due to impaired placental implantationPoor wound healing and abnormal scar formationDeep muscle hematomas and hemarthrosesNormal PT, aPTT, platelet count, and bleeding time despite severe bleedingPositive urea clot solubility test in severe deficiency
From Orphanet’s phenotype annotations (CC BY 4.0). Not a complete list.
Before you apply
Things trial teams commonly ask about for Factor XIII Deficiency. Not eligibility rules; those are set by each study.
- 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.
Related conditions
Information, not medical advice. Trial listings are shown as recorded on ClinicalTrials.gov; whether any study is right for you is a decision for you and your clinicians, and eligibility is decided by each research team. Disease information from Orphanet (CC BY 4.0).