An observational study in Factor X Deficiency, sponsored by Fondazione Luigi Villa. Recruiting at 2 sites in Italy. Per ClinicalTrials.gov, last updated 2026-10-20.
Sponsored by Fondazione Luigi Villa · Observational
Factor X deficiency is one of the most severe rare bleeding disorders and may lead to serious spontaneous hemorrhages, particularly in patients with severe congenital forms. Acquired FX deficiency is even rarer, most frequently associated with AL amyloidosis, and remains poorly characterized. Establishing a comprehensive patient registry is essential to improve understanding of disease epidemiology, clinical manifestations, and treatment outcomes, ultimately supporting evidence-based management strategies.
Factor X deficiency is a rare coagulation disorder that exists in both congenital and acquired forms. Despite its rarity, it represents a clinically important condition because of its potential to cause significant bleeding complications and the limited evidence available to guide patient management.
The congenital form is characterized by a wide spectrum of clinical severity ranging from mild bleeding manifestations to life-threatening hemorrhages. Clinical presentation may vary considerably among patients, making diagnosis and long-term management challenging. Even individuals with partially reduced FX levels may experience clinically relevant bleeding episodes requiring medical intervention.
Acquired FX deficiency is an exceptionally uncommon disorder. Diagnosis relies on recognizing a characteristic laboratory profile and differentiating it from inherited forms and other causes of abnormal coagulation tests. The condition is most commonly linked to underlying systemic diseases, particularly AL amyloidosis, while other etiologies are infrequently reported. Because only a limited number of cases have been documented, knowledge regarding optimal treatment approaches remains scarce.
Given these challenges, systematic collection of clinical, laboratory, and treatment data through dedicated registries is critical. Such initiatives can facilitate a better understanding of disease patterns, diagnostic pathways, therapeutic practices, and long-term outcomes, thereby supporting future research and improving patient care.
Fondazione Luigi Villa is the lead sponsor of 2 studies on the registry; 2 are open to participants now.
Counted across the registry records on this site, refreshed daily.
The criteria were revised on the registry on Oct 20, 2026. See what changed
males and females of any age affected with FX deficiency of any severity as well as their first degree family members
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
males and females of any age affected with FX deficiency of any severity and family members
Bleedings
To estimate total bleed rates including major, minor, spontaneous and non-spontaneous episodes in patients with FX deficiency
Time frame: 3 years
Bleeding severity
To estimate bleed rates according to the severity (major or minor) and modality (spontaneous or non-spontaneous) of episodes in patients with FX deficiency
Time frame: 3 years
Bleeding predictors 1
To identify potential predictors of bleeding episodes based on FX plasma levels,
Time frame: 3 years
Bleeding predictors 2
To identify potential predictors of bleeding episodes based on treatment approaches (on-demand vs. prophylactic)
Time frame: 3 years
Quality of LIfe
To assess longitudinal changes in patients' quality of life using the EQ-5D-5L qeustionnaire at enrollment and at close-out visit
Time frame: 3 years
Plan to share: No
No publications or documents are linked to this record.
Started Jun 2026 (actual). Primary completion is estimated for Jun 2028, 24 months after the start.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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Factor X Deficiency