Congenital Prothrombin Deficiency: Comprehensive Disease-Characteristics Report

Executive summary

Congenital prothrombin deficiency is an ultra-rare, usually autosomal-recessive bleeding disorder caused by biallelic pathogenic variants in F2, which encodes the vitamin-K-dependent zymogen prothrombin (factor II). It comprises quantitative hypoprothrombinemia and qualitative dysprothrombinemia. Estimated prevalence is approximately 1 per 2,000,000, although ascertainment is incomplete and prevalence is higher in populations with substantial consanguinity. Complete F2 deficiency has not been documented in living humans and is considered incompatible with survival. Clinical expression ranges from incidental coagulation-test abnormalities to neonatal or childhood mucosal, soft-tissue, gastrointestinal, joint, intracranial, surgical, and obstetric hemorrhage. Diagnosis rests on prolonged PT and aPTT, reduced factor-II coagulant activity, antigen measurement, exclusion of acquired causes, and molecular confirmation. There is no generally available specific factor-II concentrate; bleeding and procedures are managed mainly with prothrombin-complex concentrate (PCC), or fresh-frozen plasma (FFP) when PCC is unavailable. Evidence remains dominated by case reports, small series, expert reviews, and model-organism studies rather than prospective trials. (castaman2017diagnosisandtreatment pages 10-11, menegatti2020clinicalandlaboratory pages 1-2, lancellotti12009congenitalprothrombindeficiency pages 2-4)

The following table provides a compact knowledge-base representation; the narrative afterward supplies qualification and mechanistic detail.

Table: Concise knowledge-base summary of congenital prothrombin deficiency, including genetics, phenotypes, diagnostics, treatment targets, models, ontology suggestions, and major evidence gaps.

1. Disease information

Definition and classification

Congenital prothrombin deficiency is an inherited defect of secondary hemostasis caused by deficient quantity or function of factor II. Two biochemical classes are recognized:

• Type I, hypoprothrombinemia: concordantly reduced factor-II activity and prothrombin antigen.
• Type II, dysprothrombinemia: reduced activity despite normal or near-normal antigen, indicating a dysfunctional circulating protein.

The distinction is laboratory-biochemical rather than a separate etiologic disease classification. Reviews often classify residual activity as severe <5%, moderate 5–10%, and mild >10%, but these thresholds are not prospectively validated diagnostic criteria. (lancellotti12009congenitalprothrombindeficiency pages 2-4)

Identifiers and synonyms

• MONDO: MONDO:0013361.
• Causal target: F2; Ensembl ENSG00000180210; approved name “coagulation factor II, thrombin.” Open Targets identifies F2 as the sole associated target and ClinGen’s Hemostasis/Thrombosis Gene Curation Expert Panel classifies the gene–disease relationship as Definitive with autosomal-recessive inheritance. (OpenTargets Search: congenital prothrombin deficiency-F2)
• Common names: congenital prothrombin deficiency, congenital factor II deficiency, hereditary factor II deficiency, hypoprothrombinemia, and dysprothrombinemia.
• Coding caveat: exact current OMIM, Orphanet, MeSH, ICD-10, and ICD-11 identifiers were not verified in the retrieved source text. These should be imported directly from the respective controlled terminologies rather than inferred. Broad ICD coding commonly groups this disorder under “hereditary deficiency of other clotting factors,” but jurisdiction-specific verification is required.

This report synthesizes aggregated disease-level resources, reviews, and published patient cohorts/case studies. It is not derived from an individual EHR.

2. Etiology, risk, protection, and environment

Primary cause

The disease is caused by germline F2 variants that reduce prothrombin synthesis, secretion, stability, activation, substrate recognition, or catalytic/procoagulant performance. Homozygous and compound-heterozygous states generally cause clinically important deficiency; heterozygotes are usually asymptomatic or mildly affected. Complete absence appears lethal. (OpenTargets Search: congenital prothrombin deficiency-F2, lancellotti12009congenitalprothrombindeficiency pages 2-4, jayandharan2005moleculargeneticsof pages 6-7)

Genetic risk factors

The principal risk factor is inheriting two pathogenic F2 alleles. Family history and parental consanguinity increase prior probability. Representative mechanisms include missense substitutions, in-frame deletions, frameshift alleles, splice abnormalities, and deletions. Examples include Arg271Cys, associated in one primary study with factor-II activity of 10.2% and severe bleeding; Ala362Thr/Prothrombin Vellore 1, adjacent to catalytic His363/Cys364; an Arg−1Gln processing-site substitution; Arg457Gln in reported Puerto Rican families; and Prothrombin Edmonton R−4Q in compound heterozygosity with a deletion. (jayandharan2005moleculargeneticsof pages 6-7, wong2006severeprothrombindeficiency pages 6-6)

The common F2 G20210A thrombophilia allele is mechanistically and clinically distinct: it raises prothrombin and predisposes to thrombosis rather than causing congenital factor-II deficiency. Antithrombin-resistant dysprothrombin variants can also produce thrombosis and should not automatically be grouped with bleeding-causing F2 loss of function.

Environmental and gene–environment interactions

No toxin, infection, diet, occupation, or lifestyle exposure causes the congenital disorder. Environmental and physiological challenges modify bleeding expression: trauma, dental work, surgery, menstruation, pregnancy/childbirth, and anticoagulant or antiplatelet exposure can reveal otherwise mild disease. Vitamin-K deficiency, liver disease, disseminated intravascular coagulation, and vitamin-K antagonists lower factor II through acquired mechanisms and can amplify bleeding, but are differential diagnoses rather than causes of congenital F2 deficiency.

No validated protective genetic variant, modifier gene, diet, or lifestyle intervention prevents congenital deficiency. Practical protection consists of avoiding unnecessary trauma and drugs that impair hemostasis, correcting superimposed vitamin-K deficiency, and providing planned hemostatic cover. Evidence for epigenetic modifiers or reproducible gene–environment interactions is unavailable.

3. Phenotypes

The phenotype is a variable, lifelong bleeding diathesis. Severe disease may become evident neonatally or in childhood; milder disease may remain unrecognized until surgery, dental extraction, menarche, childbirth, or trauma. Bleeding is episodic rather than anatomically progressive. Individuals carrying the same variant may differ clinically. (lancellotti12009congenitalprothrombindeficiency pages 2-4)

Suggested HPO annotations include:

• easy bruising/ecchymosis — HP:0000978;
• hematoma — HP:0001020;
• epistaxis — HP:0000421;
• gingival/oral bleeding — HP:0000225 or the closest current HPO bleeding term;
• menorrhagia/heavy menstrual bleeding — HP:0000132;
• prolonged postoperative bleeding — HP:0004846;
• gastrointestinal hemorrhage — HP:0002239;
• hemarthrosis — HP:0005261;
• muscle hemorrhage — HP:0012233, subject to ontology-version verification;
• intracranial hemorrhage — HP:0002170;
• prolonged PT and prolonged aPTT — use current HPO laboratory terms after terminology validation;
• reduced factor-II activity — a specific laboratory ontology concept may be preferable if HPO granularity is inadequate.

Recurrent mucocutaneous and gynecologic bleeding predominates in severe deficiency; hemarthrosis and muscle bleeding are less common than in severe hemophilia. Reviews also document gastrointestinal and intracranial hemorrhage and bleeding after surgery or dental extraction. Menorrhagia was estimated in approximately 20% of homozygous women in one review, but reliable frequencies for most manifestations do not exist because patient numbers are extremely small. (castaman2017diagnosisandtreatment pages 10-11, lancellotti12009congenitalprothrombindeficiency pages 2-4)

Quality-of-life burdens plausibly include activity restriction, anxiety around procedures, iron deficiency from mucosal or menstrual loss, hospital attendance, and reproductive-health burden. However, no disease-specific EQ-5D, SF-36, PROMIS, or validated patient-reported-outcome dataset was identified.

4. Genetic and molecular information

Gene and protein

F2 lies on chromosome 11p11–q12 and encodes prothrombin, a liver-synthesized vitamin-K-dependent plasma glycoprotein. The precursor contains a signal peptide, propeptide, γ-carboxyglutamate (Gla) domain, two kringle domains, and a serine-protease region that becomes thrombin’s A and catalytic B chains. Factor Xa within the prothrombinase complex cleaves prothrombin at Arg273 and Arg322 to generate thrombin. (castaman2017diagnosisandtreatment pages 10-11, lancellotti12009congenitalprothrombindeficiency pages 2-4, grzegorski2020disruptionofthe pages 1-2)

Suggested annotations include HGNC:3535 for F2, subject to direct HGNC verification; GO:0007596 blood coagulation; GO:0072378 blood coagulation, fibrin-clot formation; GO:0006508 proteolysis; and plasma/extracellular-space cellular-component terms. Relevant chemicals include vitamin K and calcium ions; exact ChEBI identifiers should be checked against the current release.

Variant interpretation

Disease-causing variants are germline. Current pathogenicity and population frequency must be curated variant by variant from ClinVar and gnomAD using a normalized transcript and HGVS expression; historical protein numbering is inconsistent because publications may count or exclude the signal peptide/propeptide. Consequently, synonymous names such as Ala362Thr versus mature/full-length numbering should not be merged without transcript-level reconciliation.

A 2005 Indian study identified four missense variants and one in-frame deletion, with none predicted to abolish protein completely. Functional/structural analysis suggested that Prothrombin Vellore 1 disrupts the conserved active-site environment and that Arg−1Gln impairs precursor processing. This illustrates why F2 variants may produce combined quantitative and qualitative abnormalities. (jayandharan2005moleculargeneticsof pages 6-7)

A recent 2023 study sequenced 12 southeastern Iranian patients and reported an exon-7 substitution in three and an exon-14 frameshift caused by thymine insertion at positions 1760–1761 in one. The authors did not establish a statistically significant mutation–clinical-symptom relationship, emphasizing the limitations of very small cohorts. Publication: February 2023; DOI: https://doi.org/10.34172/cjmb.2023.10. (samarkhazan2023determinationoffactor pages 6-6)

No established chromosomal syndrome, recurrent aneuploidy, somatic F2 mechanism, repeat expansion, mitochondrial defect, or disease-specific epigenetic lesion is recognized. No consistently validated modifier gene or protective allele has been established.

5. Environmental information

Environmental exposures are not etiologic. The clinically relevant external factors are hemostatic stressors and iatrogenic modifiers: trauma, surgery, invasive dental procedures, childbirth, anticoagulants, antiplatelet drugs, and possibly NSAIDs. Liver dysfunction or poor vitamin-K availability may superimpose acquired hypoprothrombinemia. No infectious agent or zoonotic transmission applies.

6. Mechanism and pathophysiology

Ordered causal chain

1. Biallelic F2 mutation leads to reduced synthesis/secretion/stability of prothrombin, or production of dysfunctional prothrombin.
2. Reduced circulating functional prothrombin leads to inadequate factor-Xa/prothrombinase-mediated conversion of prothrombin to thrombin.
3. Reduced thrombin generation leads to impaired fibrinogen cleavage and reduced fibrin formation.
4. Reduced thrombin generation also leads to weaker platelet activation, deficient amplification through factors V, VIII, and XI, and reduced factor-XIII activation.
5. These defects result in a weak, slowly forming, inadequately stabilized hemostatic clot.
6. Hemostatic challenge then leads to prolonged mucosal, soft-tissue, surgical, menstrual, gastrointestinal, joint, muscle, intracranial, or obstetric bleeding.
7. Branch—quantitative disease: defective transcription, processing, secretion, or stability results in low activity and low antigen.
8. Branch—qualitative disease: impaired activation, substrate recognition, or catalytic function results in low activity despite normal or near-normal antigen.
9. Inferred survival constraint: near-total loss of thrombin generation leads to developmental/perinatal hemorrhage and lethality, supported strongly by mouse and fish models but not directly demonstrable in humans. (lancellotti12009congenitalprothrombindeficiency pages 2-4, grzegorski2020disruptionofthe pages 4-6, grzegorski2020disruptionofthe pages 1-2)

This is the common coagulation pathway, not a canonical Wnt/MAPK/mTOR disease. Upstream processes are F2 expression, vitamin-K-dependent γ-carboxylation, secretion, and prothrombinase activation; downstream processes are thrombin-dependent fibrin formation, platelet activation, coagulation amplification, and clot stabilization.

A zebrafish kringle-1 mutation provides direct mechanistic evidence. A 14-bp genomic deletion caused abnormal splicing; 98.8% of mutant reads used a cryptic acceptor to produce a 45-bp in-frame deletion, and homozygous embryos showed a 45% transcript reduction. Engineered human Δ15 prothrombin had impaired secretion, approximately threefold slower activation, and reduced fibrinogen cleavage despite preserved activity against a small synthetic substrate. Thus, normal amidolytic activity does not guarantee physiological clotting function. (grzegorski2020disruptionofthe pages 4-6, grzegorski2020disruptionofthe pages 7-9)

Principal cells are hepatocytes, which synthesize prothrombin; platelets, which assemble prothrombinase and respond to thrombin; and vascular endothelial cells, whose injury initiates hemostasis. Suggested Cell Ontology terms are CL:0000182 hepatocyte, CL:0000233 platelet, and CL:0000115 endothelial cell. No primary inflammatory, autoimmune, apoptotic, energetic-metabolic, or infectious mechanism is established.

Disease-specific transcriptomic, proteomic, metabolomic, lipidomic, single-cell, spatial-transcriptomic, or multi-omics signatures have not been established. No disease-focused CRISPR therapeutic screen was identified; genome editing has instead been used to create fish models.

7. Anatomical structures affected

The defect is systemic and circulatory rather than confined to one organ. Primary functional compartments are liver—site of synthesis—and blood/plasma—site of prothrombin circulation and coagulation. Suggested UBERON terms include liver UBERON:0002107, blood UBERON:0000178, blood vessel UBERON:0001981, and bone joint UBERON:0000982, subject to release verification.

Secondary injury may affect skin/subcutis, nasal and oral mucosa, uterus/endometrium, gastrointestinal tract, skeletal muscle, joints, and brain, depending on hemorrhage. There is no intrinsic lateralization; lesions may be unilateral, bilateral, or multifocal according to the bleeding event.

At subcellular level, synthesis and processing involve hepatocyte rough endoplasmic reticulum and Golgi; mature prothrombin acts in extracellular plasma and on phospholipid membrane surfaces. Relevant GO cellular-component terms include extracellular region/plasma and endoplasmic-reticulum/Golgi compartments.

8. Temporal development

The genetic lesion is congenital and lifelong. Severe surviving cases can manifest in the neonatal period or childhood; moderate/mild cases may first present in adolescence or adulthood after a challenge. The biochemical deficiency is generally stable and nonprogressive, while bleeding is episodic and exposure-dependent. There are no formal stages or spontaneous molecular remission. Apparent clinical remission means absence of bleeding between challenges, not correction of F2 deficiency.

Critical periods include delivery/neonatal life, childhood trauma, menarche and reproductive years, pregnancy/childbirth, and invasive procedures. Planned replacement before procedures is the principal intervention window.

9. Inheritance and population

Inheritance is predominantly autosomal recessive; ClinGen regards the F2 relationship as definitive. Biallelic disease affects males and females, and population prevalence is estimated near 1:2,000,000 for severe deficiency. Incidence per 100,000 person-years is not established. Consanguinity increases prevalence, and reported geographic clusters often reflect ascertainment or founder alleles rather than environmental endemicity. (OpenTargets Search: congenital prothrombin deficiency-F2, menegatti2020clinicalandlaboratory pages 1-2)

Expressivity is variable, including among individuals with the same mutation. Penetrance for severe biallelic loss is probably high but is not quantified; heterozygous penetrance is low and may be challenge-dependent. Anticipation is not expected. Germline mosaicism is theoretically possible but not established as a recurrent mechanism.

Arg457Gln has linked reported Puerto Rican kindreds, while variants described in India and southeastern Iran indicate regional/founder effects. Robust carrier frequencies by ancestry are unavailable. Under Hardy–Weinberg assumptions, a disease prevalence of 1/2,000,000 would imply an aggregate pathogenic-allele frequency near 1/1,414 and carrier frequency near 1/707, but this is only a rough model and should not replace empirical screening data.

10. Diagnostics

Laboratory approach

1. Document personal and family bleeding history using a standardized bleeding-assessment tool where possible.
2. Obtain CBC/platelets, PT/INR, aPTT, fibrinogen, thrombin time as appropriate, liver tests, and medication/vitamin-K history.
3. Congenital factor-II deficiency usually prolongs both PT and aPTT, because F2 is in the common pathway.
4. Perform mixing studies if an inhibitor is possible; correction supports a deficiency.
5. Confirm reduced factor-II coagulant activity using a one-stage assay, with attention to reagent sensitivity and anticoagulant interference.
6. Measure prothrombin antigen: low activity plus low antigen supports hypoprothrombinemia; low activity with normal/near-normal antigen supports dysprothrombinemia.
7. Exclude acquired vitamin-K deficiency, warfarin effect, liver disease, DIC, massive transfusion/dilution, and acquired inhibitors.
8. Confirm with F2 sequencing and deletion/duplication analysis; test parents/relatives for segregation when feasible. (menegatti2020clinicalandlaboratory pages 1-2, lancellotti12009congenitalprothrombindeficiency pages 2-4)

Single-gene testing or a hereditary-bleeding-disorder panel is first line. WES/WGS can identify deep intronic, structural, or alternative diagnoses after negative targeted testing, but interpretation should remain anchored to activity/antigen results. CMA, karyotyping, FISH, mitochondrial sequencing, and repeat-expansion tests are not routine. RNA studies can clarify suspected splice defects but are not established general diagnostics.

Imaging is complication-directed: head CT/MRI for suspected intracranial hemorrhage; ultrasound/CT for abdominal bleeding; musculoskeletal ultrasound or MRI for muscle/joint hemorrhage. Biopsy and electrophysiological testing have no routine diagnostic role.

Differential diagnosis

Distinguish from deficiencies of factors V or X, combined vitamin-K-dependent factor deficiency, fibrinogen disorders, severe liver disease, vitamin-K deficiency/warfarin exposure, DIC, lupus anticoagulant or a specific inhibitor, and preanalytical coagulation-sample error. A normal factor-II antigen with low activity suggests dysprothrombinemia; proportionate reductions in factors II, VII, IX, and X suggest vitamin-K deficiency, warfarin effect, or combined vitamin-K-dependent factor deficiency rather than isolated F2 disease.

There is no population newborn-screening program. Appropriate strategies are cascade testing in known families, partner testing where relevant, prenatal diagnosis after familial-variant identification, and preimplantation genetic testing after counseling.

11. Outcome and prognosis

No reliable 5-year/10-year survival, mortality rate, or life-expectancy estimate exists. With recognition and access to replacement, many patients can achieve effective hemostasis and normal or near-normal life participation. Severe gastrointestinal, intracranial, neonatal, surgical, or obstetric hemorrhage can nevertheless cause death or permanent disability. Prognosis depends on residual functional activity, variant mechanism, previous bleeding phenotype, access to specialist treatment, and exposure to hemostatic challenges. (castaman2017diagnosisandtreatment pages 10-11, lancellotti12009congenitalprothrombindeficiency pages 2-4)

Potential morbidity includes anemia, joint or muscle damage after recurrent deep bleeding, neurological disability after intracranial hemorrhage, procedure avoidance, reproductive complications, and treatment-related thrombosis or fluid overload. No validated molecular prognostic biomarker exists beyond factor-II activity/antigen and personal bleeding history.

12. Treatment

Replacement and adjunctive care

For clinically important bleeding or invasive procedures, expert reviews recommend PCC 20–30 IU/kg, repeated according to clinical response and measured factor-II level. Suggested targets are approximately 20–30% for hemostasis and 30–40% for major surgery. PCC is practical because it contains factor II, but also supplies factors VII, IX, and X; repeated dosing can accumulate long-half-life factors and create thrombotic risk. (castaman2017diagnosisandtreatment pages 10-11)

When PCC is unavailable, FFP 15–20 mL/kg can replace factor II, although larger volumes create fluid-overload and transfusion risks. A purified, generally available specific factor-II concentrate is lacking. (castaman2017diagnosisandtreatment pages 10-11)

Tranexamic acid or another antifibrinolytic can be considered for oral, nasal, menstrual, or dental bleeding, alongside local pressure, suturing, topical hemostatic materials, and dental planning. Antifibrinolytics do not correct the common-pathway defect and are inadequate alone for major bleeding. Iron replacement and menstrual suppression may be useful supportive interventions. Desmopressin is not a factor-II replacement and has no disease-specific mechanistic rationale.

Suggested NCIt intervention concepts include Prothrombin Complex Concentrate, Fresh Frozen Plasma Transfusion, Tranexamic Acid, Antifibrinolytic Therapy, and perioperative hemostatic management; exact NCIt codes require terminology lookup.

Strategy by setting

• Minor mucosal/dental bleeding: local measures ± antifibrinolytic; add PCC/FFP based on severity and previous phenotype.
• Major bleeding: urgent PCC, monitor factor-II activity and clinical hemostasis; use FFP if PCC is unavailable.
• Major surgery: multidisciplinary plan, raise factor II to approximately 30–40%, repeat based on half-life, levels, wound hemostasis, and thrombosis risk.
• Pregnancy/delivery: individualized hematology–obstetric plan; assess activity and bleeding history, arrange replacement for delivery and postpartum risk, and avoid neuraxial procedures unless coagulation has been adequately corrected. Disease-specific pregnancy outcome data are sparse.
• Long-term prophylaxis: may be considered after recurrent severe bleeding, but evidence is limited to case experience; routine schedules are not standardized.

No approved gene, cell, RNA, or F2-targeted replacement therapy was identified. No disease-specific interventional ClinicalTrials.gov study was found in the tool search; retrieved studies concerned unrelated acquired coagulation settings. This means no relevant trial was identified, not proof that none exists globally.

Recent expert reviews conclude that although epidemiology, genetics, and diagnosis of rare bleeding disorders have advanced, management remains constrained by limited factor products and sparse trial evidence. Interest is growing in rebalancing agents that enhance coagulation or inhibit natural anticoagulant pathways, but this is not established therapy for congenital prothrombin deficiency.

13. Prevention

Primary prevention of the mutation is not possible through vaccination, diet, or environmental modification. Reproductive options include autosomal-recessive risk counseling, cascade carrier testing, prenatal diagnosis, and preimplantation genetic testing when familial variants are known. For two confirmed carriers, each pregnancy has a 25% probability of biallelic disease, 50% probability of carrier status, and 25% probability of inheriting neither familial allele.

Secondary prevention consists of early diagnosis in relatives, documenting the disorder in emergency records, and obtaining a baseline factor-II activity and individualized bleeding plan. Tertiary prevention includes planned perioperative replacement, early treatment of bleeding, avoidance of unnecessary aspirin/NSAIDs and anticoagulants, dental prevention, iron monitoring, and postpartum surveillance. Immunization has no disease-specific role, although standard vaccines should not be withheld; pressure after injections and an individualized route may be appropriate in severe bleeding disorders.

14. Other species and natural disease

No well-established naturally occurring veterinary counterpart specific to F2 deficiency was identified. Therefore, breed associations, VBO terms, veterinary prevalence, and zoonotic transmission are unavailable or not applicable. F2 orthologs and thrombin function are strongly conserved among vertebrates. Relevant taxa include Mus musculus (NCBI Taxon 10090), Danio rerio (7955), and Oryzias latipes (8090). This is a genetic coagulation disorder and has no zoonotic potential.

15. Model organisms

Mouse

Homozygous F2 disruption causes embryonic hemorrhage, approximately 50% mortality by embryonic day 10.5, and fatal neonatal/postnatal hemorrhage in survivors. The model establishes that complete prothrombin loss has developmental and survival consequences beyond ordinary provoked bleeding. Its limitation is early lethality, which restricts study of chronic adult disease. Transgenic prothrombin expression can rescue aspects of lethality. (grzegorski2020disruptionofthe pages 1-2, lancellotti12009congenitalprothrombindeficiency pages 7-8)

Zebrafish

A targeted kringle-1-domain f2 lesion allows normal development into the mid-juvenile period but prevents occlusive arterial and venous thrombosis after endothelial injury. Internal hemorrhage begins around one month; 23 of 24 homozygotes died by 90 days. Bleeding occurred around the head, jaw, muscle, fins, heart, and abdomen. The model separates relatively preserved thrombocyte attachment/primary hemostasis from severely defective thrombin-dependent secondary hemostasis and permits in-vivo study beyond stages lethal in mice. Species-specific blood pressure, aquatic development, and lack of birth trauma limit direct translation. Publication: March 2020; DOI: https://doi.org/10.1038/s41598-020-60840-7. (grzegorski2020disruptionofthe pages 4-6, grzegorski2020disruptionofthe pages 7-9, grzegorski2020disruptionofthe pages 1-2)

The paper’s abstract states that mutants “develop normally into the mid-juvenile stage but demonstrate complete mortality by 2 months of age primarily due to internal hemorrhage,” and that engineered human prothrombin showed “a severe reduction in secretion, thrombin generation, and fibrinogen cleavage.” These are model-organism and in-vitro human-protein findings, respectively, not clinical treatment evidence. (grzegorski2020disruptionofthe pages 1-2)

Medaka

Genome-edited thrombin-deficient medaka remain viable and show markedly retarded blood coagulation, including an effect in heterozygotes. This model is experimentally convenient but does not reproduce the mammalian lethality or the full human genotype–phenotype spectrum.

Recent developments and evidence assessment

The most disease-specific 2023 development located was sequencing of 12 Iranian patients, which added candidate exon-7 and exon-14 variants but lacked power for genotype–phenotype conclusions. Broader 2023–2024 literature has focused on perioperative management and the continuing therapeutic limitations across rare inherited bleeding disorders rather than on disease-specific trials. Consequently, older landmark molecular and animal studies remain essential to current understanding.

Evidence quality is highest for F2 causality and the central biochemical mechanism, supported by definitive ClinGen curation, human segregation/functional studies, and knockout models. Evidence is moderate for diagnostic activity/antigen classification and PCC/FFP practice, based on expert reviews and accumulated clinical experience. Evidence is low for phenotype frequencies, pregnancy outcomes, prophylaxis schedules, quality of life, survival, pharmacogenomics, and advanced therapies because prospective congenital-prothrombin-deficiency cohorts are absent. (OpenTargets Search: congenital prothrombin deficiency-F2, castaman2017diagnosisandtreatment pages 10-11, menegatti2020clinicalandlaboratory pages 1-2, jayandharan2005moleculargeneticsof pages 6-7)

Key cited publications and URLs

• Lancellotti S, De Cristofaro R. Congenital Prothrombin Deficiency. Seminars in Thrombosis and Hemostasis. June 2009;35:367–381. DOI: https://doi.org/10.1055/s-0029-1225759. (lancellotti12009congenitalprothrombindeficiency pages 2-4)
• Castaman G, Linari S. Diagnosis and Treatment of von Willebrand Disease and Rare Bleeding Disorders. Journal of Clinical Medicine. April 2017;6:45. DOI: https://doi.org/10.3390/jcm6040045. (castaman2017diagnosisandtreatment pages 10-11)
• Menegatti M, Palla R. Clinical and laboratory diagnosis of rare coagulation disorders. Thrombosis Research. December 2020;196:603–608. DOI: https://doi.org/10.1016/j.thromres.2019.09.006. (menegatti2020clinicalandlaboratory pages 1-2)
• Jayandharan G et al. Molecular genetics of hereditary prothrombin deficiency in Indian patients: identification of a novel Ala362→Thr mutation. Journal of Thrombosis and Haemostasis. July 2005. DOI: https://doi.org/10.1111/j.1538-7836.2005.01402.x. (jayandharan2005moleculargeneticsof pages 6-7)
• Grzegorski SJ et al. Disruption of the kringle 1 domain of prothrombin leads to late onset mortality in zebrafish. Scientific Reports. March 2020;10:4049. DOI: https://doi.org/10.1038/s41598-020-60840-7. (grzegorski2020disruptionofthe pages 4-6, grzegorski2020disruptionofthe pages 1-2)
• Samarkhazan HS et al. Determination of Factor II Codons Genotype in Southeastern Iranian Patients With Hereditary Deficiency of Factor II. February 2023;10(2):61–66. DOI: https://doi.org/10.34172/cjmb.2023.10. (samarkhazan2023determinationoffactor pages 6-6)

PMIDs explicitly linked by the retrieved Open Targets evidence to historical F2 variant literature include 1421398, 1349838, 3567158, 3801671, 22028381, 6405779, 1354985, 7792730, 3771562, and 2719946; exact mapping of each PMID to normalized HGVS variants should be verified before variant-level knowledge-base ingestion. (OpenTargets Search: congenital prothrombin deficiency-F2)

References

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8. (grzegorski2020disruptionofthe pages 4-6): Steven J. Grzegorski, Zhilian Hu, Yang Liu, Xinge Yu, Allison C. Ferguson, Hasam Madarati, Alexander P. Friedmann, Deepak Reyon, Paul Y. Kim, Colin A. Kretz, J. Keith Joung, and Jordan A. Shavit. Disruption of the kringle 1 domain of prothrombin leads to late onset mortality in zebrafish. Mar 2020. URL: https://doi.org/10.1038/s41598-020-60840-7, doi:10.1038/s41598-020-60840-7. This article has 29 citations and is from a peer-reviewed journal.

9. (samarkhazan2023determinationoffactor pages 6-6): Hamed Soleimani Samarkhazan, Shaban Alizadeh, Ziba Majidi, Zahra Kashani Khatib, and Majid Naderi. Determination of factor ii codons genotype in southeastern iranian patients with hereditary deficiency of factor ii. Crescent Journal of Medical and Biological Sciences, 10(2):61-66, Feb 2023. URL: https://doi.org/10.34172/cjmb.2023.10, doi:10.34172/cjmb.2023.10. This article has 3 citations.

10. (grzegorski2020disruptionofthe pages 7-9): Steven J. Grzegorski, Zhilian Hu, Yang Liu, Xinge Yu, Allison C. Ferguson, Hasam Madarati, Alexander P. Friedmann, Deepak Reyon, Paul Y. Kim, Colin A. Kretz, J. Keith Joung, and Jordan A. Shavit. Disruption of the kringle 1 domain of prothrombin leads to late onset mortality in zebrafish. Mar 2020. URL: https://doi.org/10.1038/s41598-020-60840-7, doi:10.1038/s41598-020-60840-7. This article has 29 citations and is from a peer-reviewed journal.

11. (lancellotti12009congenitalprothrombindeficiency pages 7-8): Stefano Lancellotti1 and Raimondo De Cristofaro1. Congenital prothrombin deficiency. Semin Thromb Hemost, 35:367-381, Jun 2009. URL: https://doi.org/10.1055/s-0029-1225759, doi:10.1055/s-0029-1225759. This article has 92 citations.

Artifacts

• Edison artifact artifact-00

Reference Validation

Checked with linkml-reference-validator 0.2.1.

All extracted references resolved successfully.

Term Validation

Checked with linkml-term-validator 0.4.5, through the ols: adapter.

Terms the report names something else

These identifiers resolve, so nothing about them looks wrong, and the ontology calls them something unrelated to what the report calls them. That usually means the identifier is not the one the sentence needs:

• MONDO:0013361 (4 mentions) - the report calls it "if available"; MONDO calls it congenital prothrombin deficiency

Unresolved terms

These identifiers do not exist in an ontology that resolved other terms from the same prefix, so they were most likely invented:

• HP:0001020 (2 mentions) - HP does not contain this term