University Clinic Bonn Institute of Experimental Haematology and Transfusion Medicine Director: Prof. Dr. Johannes Oldenburg
Introduction to FXIII Deficiency


Coagulation factor XIII (FXIII), that belongs to a family of transglutaminases, is the last enzyme to be activated the blood coagulation pathway and functions to cross-link - and -fibrin chains, resulting in a stronger clot with an increased resistence to fibrinolysis (1). Congenital factor XIII deficiency is a rare autosomal recessive disorder, affecting one in 1 – 5 million individuals. The prevalence of this disorder is higher in countries where the consangineous marriages are common. The phenotype is due to the deficiency or absence of coagulation factor XIII. Patients suffering from this condition are characterized by life – long bleeding diathesis and impaired wound healing with the severity and frequency of symptoms correlating with the residual FXIII activity.
In plasma, FXIII pro – enzyme circulates in form of a tetramer composed of two catalytic A subunits bound to two carrier A subunits (A2B2) (2). Intracellularly, FXIII is found as a homodimer of the two A subunits (A2) (3).
FXIII A-Subunit is mainly synthesized in placenta, macrophages, and megakaryocytes. Each A subunit is composed of an activation peptide (residues 1-37) and 4 distinct domains: - sandwich (residues 38-183), central core (residues 184-515), barrel 1 (residues 516-627) and barrel 2 regions (residues 628-731) (4,5). The central core domain contains a catalytic triad formed through hydrogen bond interactions between C314, His373 and Asp396 (6). The site of synthesis for XIII B-Subunit has been suggested to be the liver.
The B subunit is composed of 10 tandem repeats or glycoprotein – I (GP-I) structures designated as Sushi domains (7). The A subunit constitutes the catalytic moiety and the B subunit is thought to play a role in stabilization of the A subunit. On activation by thrombin and Ca2+ the A and B subunits dissociate. The A subunit is then cleaved to produce the catalytically active form of the protein, A2*(8). A2* catalyzes the Ca2+ - dependent formation of glutamyl-lysine bonds between fibrin molecules ( and chains). Further FXIII substrates are fibronectin, vitronectin, collagen, FV, von Willebrand Factor, 2 antiplasmin, actin, myosin, vinculin, thrombospondin, PAI, TAFI 2.
The F13A gene maps to the short arm of chromosome 6 (p24-25) and spans >160 kb of genomic DNA. It consists of 15 exons encoding a mature protein of 731 amino acids (9,10). The F13B gene is located on the long arm of chromosome 1 (q32-32.1) and contains 12 exons encoding the mature protein of 641 amino acids (11,12).

Clinical manifestations

Factor XIII was discovered in 1944 by K.C. Robbins (13). Sixteen years later, the first case of severe FXIII deficiency was described in a swiss boy with bleeding diathesis in whom the only abnormality in the clotting tests was the solubility of his clots in 5M urea (14). Since that original description over 300 cases have been reported from all parts of the world.
Patients with FXIII deficiency have a bleeding tendency that is usually severe. In affected individuals, the first manifestation of bleeding is from umbilical cord after birth, and this occures in 4 of 5 cases. Intracranial hemorrhage appears in one-fourth of the patients and is the leading cause of death. Superficial bruising, and hematomas in subcutaneous tissue and muscle are common, and the bleeding at these sites may recur if not treated. Patients may bleed around the joint after trauma, but spontaneous hemarthrosis is less frequent than in haemophiliacs (15). The most frequent symptom of mucosal tract bleeding (Table 1) is bleeding in the oral cavity (lips, tongue, gum), followed by menorrhagia and epistaxis. Minor or major surgery without replacement therapy in 84% patients has post-surgical bleeding. Intraperitoneal bleeding in women with reproductive age may occure (20%) at the time of ovulation (16).
Deficiency of FXIII results in "delayed bleeding" after trauma, while primary hemostasis in individuals with these traits is normal. The delayed bleeding is caused by premature lysis of hemostatic clots.
In addition to a lifelong bleeding tendency, abnormal wound healing in affected individuals and habitual spontaneous abortion in affected females are common. Wound-healing complications are probably due to fibrinolytic abnormalities and altered vascular permeability. Nowadays patients are diagnosed early and treated appropriately, so the severe bleeding complications associated with the deficiency are rarely seen.
A minority of homozygous or rarely heterozygous patients develop bleeding syndrome which only comes to light when they present with a haemorrhagic complication, e.g. after surgery (17, 18).

Table 1.
Prevalence of bleeding symptoms in
93 Iranian patients with factor XIII
deficiency according Lak et al (16).
Symtomes %
Mucosal tract bleeding
Mouth bleeding 48
Menorrhagia 35
Epistaxis 32
Hematuria 10
Gastrointerstinal bleeding 10
Soft Tissue bleeding
Umbilical cord bleeding 73
Hematoma 58
Hemathrosis 55
CNS bleeding 25
Other symptoms
Surgical bleeding 84
Miscarriages 50


The Scientific and Standardization Commmittee (SSC) in 1999 approved new classification of FXIII deficiency at the DNA level: XIIIA deficiency (former Type II deficiency) and XIIIB deficiency (former type I deficiency), and a possible combined deficiency of XIIIA and XIIIB (15).
In inherited FXIIIA deficiency (>95% of all cases) plasma levels of FXIII-A measured as functional activity or antigen are usually undetectable, whereas the FXIII-B subunit is normal or reduced. No case of FXIIIA deficiency in which the plasma levels of FXIII antigen are normal but its functional activity is impaired has been described.
FXIIIB deficient patients show low or undetectable FXIII activity, FXIIIA and FXIIIB antigen levels, while platelet FXIIIA level remains normal (see table 2).

Table 2. FXIII deficiency types.
plasma FXIII Activity  or  or
plasma FXIIIA-Ag  or  or
plasma FXIIIB-Ag  or N  or
platelet FXIII Activity  or N
platelet FXIIIA-Ag  or N
affected gene F13A F13B
Abbreviations: -mildly reduced, -reduced, -not detectable, N-normal.

Diagnosis of FXIII deficiency

The standard laboratory clotting tests (PT, aPTT, fibrinogen level, platelet counts, bleeding time) are normal in FXIII deficiency. Earlier FXIII deficiency diagnosis was mainly based on positive clot solubility test (rapid dissolution of clot in a solution of 1% monochloracetic acid or in a solution of 5M urea). It is a qualitative test and is positive only if FXIII activity in the patient’s plasma is zero, or very close to zero. If clot solubility in these reagents is found, it is important to perform some simple mixing experiments with normal plasma to make sure that the observed clot solubility is the result of FXIII deficiency and not due to the presence of a FXIII inhibitor (19).
The FXIII deficiency diagnosis should be done by estimation of FXIII activity using of one of the several quantitative, assays, e.g. photometric assays (Berichrom®FXIII, Dade Behring, Marburg, Germany) or incorporation assays (dansylcadaverine-casein assay). The range of plasma FXIII activity within the normal population is very wide, ranging between 53,2% and 221,3% (mean 105%±28,56% standard deviation) of the standard normal plasma velue (20). Quantitative assays (e.g. photometric) are quite inaccurate at levels of FXIII activity between 0 and 10% of normal (19). Plasma levels, >5-30% of normal are sufficient to prevent spontaneous bleeding, but may cause bleeding after surgery / tooth extraction. The concentrations of the A and B subunits should be determined by an immunological technique (19). Conformation of the disease then is the detection of causative mutation in F13A or F13B genes.

Molecular defects in F13A gene

To date, 69 unique mutations (34 missense, 21 deletions/insertions, 9 splice site and  5 nonense) have been reported in the literature. These molecular defects do not appear to be clustered in specific regions, but are scattered throughout the F13A gene. Nevertheless the majority of missense mutations are located in the catalytical core domain, no missense mutations have been so far reported in the activation peptide. One-third of missense mutations occure at CpG dinucleotide that are known as mutations hotspot. Splice site mutation in intron 5 (IVS5-1 G>A) seems to be the most common mutation since it was already reported in 6 unrelated families from UK, Macedonia, Serbia, Kosovo, Czecz Republic and the Netherlands (21). Moreover we identified this splice site defect in further patients originating from Germany, Poland, Turkey, Greece (unpublished data). 

Molecular defects in F13B gene

To date, only 5 families (2 families from Italy and 3 families from Japan) with isolated B-subunit deficiency have been described in the literature. The lack of XIIIB-subunit most likely causes instability of XIIIA and secondary XIIIA deficiency (15). XIIIB deficiency seems to be associated with mild phenotype despite of low FXIII activity (22, 23).

The role of single nucleotide polymorphisms

The allelic variance of FXIIIA has been known for many years. Leu34 and Leu564 variants have higher FXIII specific activity, while Phe204 variant results in lower FXIII specific activity (19). Increased fibrinogen concentrations were associated with decreases in permeability, with tighter clot structures in the presence of factor XIIIA Val34 alleles compared with those in the presence of Leu34 alleles (24). A strong risk factor for myocardial infarction (P=0.002) was found in carriers  with combined status of prothrombin 20210A and FXIIIA Leu34 alleles (25). The Leu34 variant may also mitigate the severity of FXIII deficiency (19). The Phe204 polymorphism may be associated with recurrent miscarriage (20). 


Whole blood, fresh frozen plasma, stored plasma and cryoprecipitate have all been used succesfully in the treatment of FXIII deficiency and are adequate sources of FXIII. As quite low levels of FXIII in plasma are sufficient for control of bleeding and the in vivo half-life of FXIII after infusion is long (11-14 days), prophylaxis is practicable (19).
No pharmacokinetics or tolerability differences have been observed between FXIII prepared from human plasma and that from placenta (26). Nowadays patients are mainly treated by plasma-derived pasteurized concentrates (Fibrogammin P, ZLB Behring). In case of mild - moderate bleeding the recommended dosage is 20-30 IU/kg of body weight – monthly, while in severe bleeding (especially intracranial haemorrhages) the dosage must be increased up to 50 IU/kg of body weight. Half-life of FXIII is 11-14 days, therefore bleeding risk may be increased 2-3 weeks after the last infusion. The best interval between substitutions is 14 days. Pregnant females should receive prophylactic treatment as soon as possible. In addition to prophylactic therapy, affected individuals who undergo surgery or trauma will require more intensive replacement therapy (19, 27).
If FXIII concentrates are not available, fresh frozen plasma is given prophylactically in doses of 2 to 3 ml / kg of body weight every 4 to 6 weeks. Cryoprecipitate can be administered in a dose of 1 bag per 10-20 kg of body weight every 3 to 4 weeks (28).

FXIII inhibitors

In inherited FXIII deficiency inhibitors such as antibodies to injected FXIII arise very rarely. Only two cases have been published and no information on management of these cases is available (29, 30). Rarely (22 cases worldwide) FXIII inhibitors arise de novo, in the course of other diseases, e.g. in systematic lupus erythematosus (31), and often in relation to chronic therapy with a variety of drugs, e.g. isoniazid, penicillin, phenytoin, ciprofloxacin. Inhibitors may also appear in patients without any obvious chronic disease (32). Bleedings in these cases may be severe and difficult to treat. Several cases have died of cerebral haemorrhage (2, 33). Most of the inhibitors described are antibodies (IgG immunoglobulins). Treatments attempted include immunosuppresion with steroids and cyclophosphamide, administration of large doses of FXIII, and plasma immunoadsorption. Rituximab (anti-CD20 monoclonal antibody) may be also useful in the treatment of acquired FXIII deficiency (33).

Acquired FXIII deficiency

This remains a doubtful entity. Low plasma levels of FXIII activity have been reported in a whole variaty of conditions, predominantly leukemias, severe liver disease, inflammatory bowel disorders and disseminated intravascular coagulation (Table 3). In these cases, plasma FXIII levels are usually in the range of 50% to 75%. Whether the low FXIII contributes to haemorrhagic complications in these diseases remains to be proven. Treatment of patients bleeding from the small bowel in Henoch-Schölein purpura and from large bowel in ulcerative colitis with FXIII concentrate has been reported to be effective in controlling the bleeding. (34). The benefits of such therapy in these circumstances cannot be recomended until more scientific evidence emerges in support of such an approach, and the possible mechanisms of FXIII action in these situations elucidated (19).

Table 3. Diseases with aquired FXIII deficiency (from ref. 27).

  • Liver disorders
    - acute and chronic hepatitis
    - acute liver failure
  • Inflammatory bowel disorders
    - Henoch-Schönlein sindrome
    - Morbus Crohn
    - Ulcerative Colitis
    - Haemorrhagic gastritis
  • Hematological disorders
    - Leukemia
    - Myeloproliferative and mielodysplastic syndrome
  • Disseminated intravascular coagulation (DIC)
  • Sepsis
  • Major surgical interventions


1. Tuddenham EGD, Cooper DN. The Molecular Genetics of Heamostasis and its Inherited Disorders. Oxford: Oxford University Press, 1994.

2. Lorand L, Losowsky MS, Miloszewski KJ.Human factor XIII: fibrin-stabilizing factor. Prog Hemost Thromb 1980; 5: 245-90.

3. Schwartz ML, Pizzo SV, Hill RL, McKee PA.Human Factor XIII from plasma and platelets. Molecular weights, subunit structures, proteolytic activation, and cross-linking of fibrinogen and fibrin. J Biol Chem 1973; 248: 1395-407.

4. Yee VC, Pedersen LC, Le Trong I, Bishop PD, Stenkamp RE, Teller DC.Three-dimensional structure of a transglutaminase: human blood coagulation factor XIII. Proc Natl Acad Sci U S A 1994; 91:7296-300.

5. Yee VC, Pedersen LC, Bishop PD, Stenkamp RE, Teller DC.Structural evidence that the activation peptide is not released upon thrombin cleavage of factor XIII. Thromb Res 1995; 78: 389-97.

6. Pedersen LC, Yee VC, Bishop PD, Le Trong I, Teller DC, Stenkamp RE.Transglutaminase factor XIII uses proteinase-like catalytic triad to crosslink macromolecules. Protein Sci 1994; 3:1131-5.

7. Ichinose A, McMullen BA, Fujikawa K, Davie EW.Amino acid sequence of the b subunit of human factor XIII, a protein composed of ten repetitive segments. Biochemistry 1986; 25: 4633-8.

8. Takagi T, Doolittle RF. Amino acid sequence studies on Factor XIII and the peptide released during its activation by thrombin. Biochemistry 1974; 13: 750-6.

9. Ichinose A, Davie EW. Characterization of the gene for the a subunit of human factor XIII (plasma transglutaminase), a blood coagulation factor. Proc Natl Acad Sci U S A. 1988 85:5829-33.

10. Ichinose A, Davie EW. Primary structure of human coagulation factor XIII. Adv Exp Med Biol 1988; 231: 15-27.

11. Webb GC, Coggan M, Ichinose A, Board PG. Localization of the coagulation factor XIII B subunit gene (F13B) to chromosome bands 1q31-32.1 and restriction fragment length polymorphism at the locus. Hum Genet. 1989; 81: 157-60.

12. Bottenus RE, Ichinose A, Davie EW. Nucleotide sequence of the gene for the b subunit of human factor XIII. Biochemistry. 1990; 29: 11195-209.

13. Robbins KC. A study of the convertion of the fibrinogen to fibrin. Am J Physiol 1944; 142: 581-8.

14. Duckert F, Jung E, Shmerling DH. A hitherto undescribed congenital haemorrhagic diathesis probably due to fibrin stabilizing factor deficiency. Thromb Diath Haemorrh. 1960; 5:179-86.

15. Ichinose A. Physiopathology and regulation of factor XIII. Thromb Haemost 2001; 86: 57-65

16. Lak M, Peyvandi F, Ali Sharifian A, Karimi K, Mannucci PM. Pattern of symptoms in 93 Iranian patients with severe factor XIII deficiency. J Thromb Haemost. 2003; 1: 1852-3.

17. Miloszewski KJA, Losowsky MS. Fibrin stabilisation and factor XIII deficiency. In: Francis L, ed. Fibrinogen, Fibrin Stabilisation and Fibrinolysis. Chichester: Ellis Horwood, 1988: 175-202.

18. Egbring R, Seitz R, Gürten GV et al (1988) Bleeding complications in heterozygotes with congenital factor XIII deficiency. In: Mosseson MW et al (eds) Fibrinogen 3. Elsevier Science 341-446.

19. Anwar R, Miloszewski KJ. Factor XIII deficiency. Br J Haematol. 1999; 107: 468-84.

20. Anwar R, Gallivan L, Edmonds SD, Markham AF. Genotype/phenotype correlations for coagulation factor XIII: specific normal polymorphisms are associated with high or low factor XIII specific activity. Blood. 1999; 93: 897-905.

21. Schroeder V, Meili E, Cung T, Schmutz P, Kohler HP. Characterisation of six novel A-subunit mutations leading to congenital factor XIII deficiency and molecular analysis of the first diagnosed patient with this rare bleeding disorder. Thromb Haemost. 2006, 95:77-84.

22. Saito M, Asakura H, Yoshida T, Ito K, Okafuji K, Yoshida T, Matsuda T. A familial factor XIII subunit B deficiency. Br J Haematol. 1990; 74: 290-4.

23. Girolami A, Cappellato MG, Lazzaro AR, Boscaro M. Type I and type II disease in congenital factor XIII deficiency. A further demonstration of the correctness of the classification. Blut. 1986 53:411-3.

24. Lim BC, Ariens RA, Carter AM, Weisel JW, Grant PJ. Genetic regulation of fibrin structure and function: complex gene-environment interactions may modulate vascular risk. Lancet. 2003 26;361:1424-31.

25. Butt C, Zheng H, Randell E, Robb D, Parfrey P, Xie YG. Combined carrier status of prothrombin 20210A and factor XIII-A Leu34 alleles as a strong risk factor for myocardial infarction: evidence of a gene-gene interaction. Blood. 2003; 101:3037-41.

26. Brackmann HH, Egbring R, Ferster et al. Pharmacokinetics and tolerability of factor XIII concentrates prepared from human placenta or plasma: a crossover randomised study. Thromb Haemost. 1995; 74:622-5.

27. Egbring R., Seitz R., Kroeniger A. Faktor-XIII-Erkrankungen: Klinik und Therapie. In: Mueller-Berghaus G, Poetzsch B, eds. Hämostaseologie, 1st edn. Berlin: Springer Verlag, 1999: 299-302.

28. Robberts HR, Bingham MD. Other Coagulation Factor Deficiencies. In Loscalzo J., Schafer AI eds. Thrombosis and Haemorrhage, 3rd edn. Philadelphia: Lippincott Williams and Wilkins, 2003: 592-3.

29. Lorand L, Urayama T, De Kiewiet JW, Nossel HL. Diagnostic and genetic studies on fibrin-stabilizing factor with a new assay based on amine incorporation. J Clin Invest. 1969 48:1054-64.

30. Henriksson P, McDonagh J, Villa M. Type I autoimmune inhibitor of factor XIII in a patient with congenital factor XIII deficiency. Thromb Haemost 1983; 50: 272.

31. Lorand L, Velasco PT, Hill JM, Hoffmeister KJ, Kaye FJ. Intracranial hemorrhage in systemic lupus erythematosus associated with an autoantibody against actor XIII. Thromb Haemost. 2002; 88: 919-23.

32. Tosetto A, Rodeghiero F, Gatto E, Manotti C, Poli T. An acquired hemorrhagic disorder of fibrin crosslinking due to IgG antibodies to FXIII, successfully treated with FXIII replacement and cyclophosphamide. Am J Hematol. 1995 48: 34-9.

33. Miesbach W. Rituximab in the treatment of factor XIII inhibitor possibly caused by Ciprofloxacin. Thromb Haemost. 2005, 93:1001-3.

34. Lorenz R., Heimüller M., Tornieporth N. Additional substitution of factor XIII concentrate in the treatment of ulcerative colitis. FXIII: Second International Conference (ed. by J. Mcdonagh, R. Seitz and R. Egbring), pp. 241-244. F.K. Schattauer Verlagsgesellschaft mbH, Marburg.