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X Chromosome inactivation: a modifier of factor VIII and IX plasma levels and bleeding phenotype in Haemophilia carriers


Haemophilia A and B are X-linked hemorrhagic disorders caused by gene variants in the F8 and F9 genes. Due to recessive inheritance, males are affected, while female carriers are usually asymptomatic with a wide range of factor VIII (FVIII) or IX (FIX) levels. Bleeding tendency in female carriers is extremely variable and may be associated with low clotting factor levels. This could be explained by F8 or F9 genetic variations, numerical or structural X chromosomal anomalies, or epigenetic variations such as irregular X chromosome inactivation (XCI). The aim of the study was to determine whether low FVIII or FIX coagulant activity in haemophilia carriers could be related to XCI and bleeding symptoms. HUMARA assay was performed on 73 symptomatic carriers with low clotting activity ≤50 IU/dL. Bleeding Assessment Tool (BAT) from the International Society on Thrombosis and Haemostasis (ISTH) was used to describe symptoms in the cohort of carriers. In 97% of haemophilia carriers, a specific gene variant in heterozygous state was found, which alone could not justify their low FVIII or FIX levels (≤50 IU/dL). A statistical association between XCI pattern and FVIII and FIX levels was observed. Moreover, female carriers with low coagulant activity (≤20 IU/dL) and high degree of XCI ( ≥ 80:20) had a higher ISTH-BAT score than the carriers with the opposite conditions (>20 IU/dL and <80:20). In our cohort of haemophilia carriers, XCI was significantly skewed, which may contribute to the low expression of clotting factor levels and bleeding symptoms.

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Fig. 1: XCI pattern (XIP) versus coagulant factor level: distribution in carriers of haemophilia.
Fig. 2: Comparison of ISTH-BAT score between two groups of haemophilia carriers.


  1. 1.

    Mannucci PM, Tuddenham EG. The Hemophilias–from royal genes to gene therapy. N Engl J Med. 2001;344:1773–9.

    CAS  PubMed  Google Scholar 

  2. 2.

    Peyvandi F, Garagiola I, Young G. The past and future of hemophilia: diagnosis, treatments, and its complications. Lancet. 2016;388:187–97.

    PubMed  Google Scholar 

  3. 3.

    Plug I, Mauser-Bunschoten EP, Bröcker-Vriends AH, van Amstel HK, van der Bom JG, van Diemen-Homan JE, et al. Bleeding in carriers of hemophilia. Blood. 2006;108:52–6.

    CAS  PubMed  Google Scholar 

  4. 4.

    Radic CP, Rossetti LC, Abelleyro MM, Tetzlaff T, Candela M, Neme D, et al. Phenotype-genotype correlations in hemophilia A carriers are consistent with the binary role of the phase between F8 and X-chromosome inactivation. J Thromb Haemost. 2015;13:530–9.

    CAS  PubMed  Google Scholar 

  5. 5.

    Miyawaki Y, Suzuki A, Fujimori Y, Takagi A, Murate T, Suzuki N, et al. Severe hemophilia A in a Japanese female caused by an F8-intron 22 inversion associated with skewed X chromosome inactivation. Int J Hematol. 2010;92:405–8.

    PubMed  Google Scholar 

  6. 6.

    Connallon T, Clark AG. Sex-differential selection and the evolution of X inactivation strategies. PLoS Genet. 2013;94:e1003440.

    Google Scholar 

  7. 7.

    Orstavik KH. X chromosome inactivation in clinical practice. Hum Genet. 2009;126:363–73.

    PubMed  Google Scholar 

  8. 8.

    Carrel L, Willard HF. X-inactivation profile reveals extensive variability in X-linked gene expression in females. Nature 2005;434:400–4.

    CAS  PubMed  Google Scholar 

  9. 9.

    Viggiano E, Picillo E, Ergoli M, Cirillo A, Del Gaudio S, Politano L. Skewed X‐chromosome inactivation plays a crucial role in the onset of symptoms in carriers of Becker muscular dystrophy. J Gene Med. 2017;19:e2952.

    Google Scholar 

  10. 10.

    Amos-Landgraf JM, Cottle A, Plenge RM, Friez M, Schwartz CE, Longshore J, et al. X chromosome inactivation patterns of 1005 phenotypically unaffected females. Am J Hum Genet. 2006;79:493–9.

    CAS  PubMed  PubMed Central  Google Scholar 

  11. 11.

    Renault NK, Dyack S, Dobson MJ, Costa T, Lam WL, Greer WL. Heritable skewed X-chromosome inactivation leads to haemophilia A expression in heterozygous females. Eur J Hum Genet. 2007;15:628–37.

    CAS  PubMed  Google Scholar 

  12. 12.

    Favier R, Lavergne JM, Costa JM, Caron C, Mazurier C, Viémont M, et al. Unbalanced X-chromosome inactivation with a novel FVIII gene mutation resulting in severe hemophilia A in a female. Blood 2000;9613:4373–75.

    Google Scholar 

  13. 13.

    Boban A, Lambert C, Lannoy N, Hermans C. Comparative study of the prevalence of clotting factor deficiency in carriers of haemophilia A and haemophilia B. Haemophilia. 2017;23:e471–3.

    CAS  PubMed  Google Scholar 

  14. 14.

    Hermans C, Kulkarni R. Women with bleeding disorders. Haemophilia. 2018;24:29–36.

    PubMed  Google Scholar 

  15. 15.

    Srivastava A, Brewer AK, Mauser-Bunschoten EP, Key NS, Kitchen S, Llinas A, et al. Treatment guidelines working group on behalf of the world federation of hemophilia. Guidelines for the management of haemophilia. Haemophilia 2013;19:e1–47.

    CAS  PubMed  Google Scholar 

  16. 16.

    Potgieter JJ, Damgaard M, Hillarp A. One-stage vs. chromogenic assays in haemophilia A. Eur J Haematol. 2015;94:38–44.

    CAS  PubMed  Google Scholar 

  17. 17.

    James PD, Mahlangu J, Bidlingmaier C, Mingot-Castellano ME, Chitlur M, Fogarty PF, et al. Global emerging hemostasis experts panel (GEHEP). Evaluation of the utility of the ISTH-BAT in haemophilia carriers: a multinational study. Haemophilia. 2016;22:912–8.

    CAS  PubMed  Google Scholar 

  18. 18.

    Stufano F, Baronciani L, Mane-Padros D, Cozzi G, Faraudo S, Peyvandi F. A comparative evaluation of a new fully automated assay for von Willebrand factor collagen binding activity to an established method. Haemophilia. 2018;24:156–61.

    CAS  PubMed  Google Scholar 

  19. 19.

    Federici AB, Canciani MT, Forza I, Mannucci PM, Marchese P, Ware J, et al. A sensitive ristocetin co-factor activity assay with recombinant glycoprotein Ibalpha for the diagnosis of patients with low von Willebrand factor levels. Haematologica 2004;89:77–85.

    CAS  PubMed  Google Scholar 

  20. 20.

    Mazurier C, Gaucher C, Jorieux S, Parquet- Gernez A, Goudemand M. Evidence for a von Willebrand factor defect in factor VIII binding in three members of a family previously misdiagnosed mild haemophilia A and haemophilia A carriers: consequences for therapy and genetic counselling. Br J Haematol. 1990;76:372–9.

    CAS  PubMed  Google Scholar 

  21. 21.

    Miller I, Djkes DD. A simple salting out procedure for extracting DNA from human nucleated cells. Nucleic Acid Res. 1988;16:1215–20.

    CAS  PubMed  Google Scholar 

  22. 22.

    Liu Q, Nozari G, Sommer SS. Single-tube polymerase chain reaction for rapid diagnosis of the inversion hotspot of mutation in hemophilia A. Blood. 1998;92:1458–9.

    CAS  PubMed  Google Scholar 

  23. 23.

    Bagnall RD, Waseem N, Green PM, Giannelli F. Recurrent inversion breaking intron 1 of the factor VIII gene is a frequent cause of severe hemophilia A. Blood 2002;99:168–74.

    CAS  PubMed  Google Scholar 

  24. 24.

    Lee JC, Chang JG. ABO genotyping by polymerase chain reaction. J Forensic Sci. 1992;37:1269–75.

    CAS  PubMed  Google Scholar 

  25. 25.

    Ota M, Fukushima H, Kulski JK, Inoko H. Single nucleotide polymorphism detection by polymerase chain reaction-restriction fragment length polymorphism. Nat Protoc. 2007;2:2857–64.

    CAS  PubMed  Google Scholar 

  26. 26.

    Allen RC, Zoghbi HY, Moseley AB, Rosenblatt HM, Belmont JW. Methylation of HpaII and HhaI sites near the polymorphic CAG repeat in the human androgen-receptor gene correlates with X chromosome inactivation. Am J Hum Genet. 1992;51:1229–39.

    CAS  PubMed  PubMed Central  Google Scholar 

  27. 27.

    Rodeghiero F, Tosetto A, Abshire T, Arnold DM, Coller B, James P, et al. ISTH/SSC joint VWF and Perinatal/Pediatric Hemostasis Subcommittees Working Group. ISTH/SSC bleeding assessment tool: a standardized questionnaire and a proposal for a new bleeding score for inherited bleeding disorders. J Thromb Haemost. 2010;8:2063–5.

    CAS  PubMed  Google Scholar 

  28. 28.

    Elbatarny M, Mollah S, Grabell J, Bae S, Deforest M, Tuttle A, et al. Normal range of bleeding scores from the ISTH-BAT: adult and pediatric data from the merging project. Haemophilia. 2014;20:831–5.

    CAS  PubMed  PubMed Central  Google Scholar 

  29. 29.

    Peyvandi F, Mannucci PM, Garagiola I, El‑Beshlawy, Elalfy M, Ramanan V, et al. Randomized trial of factor VIII and neutralizing antibodies in hemophilia A. N Engl J Med. 2016;374:2054–64.

    CAS  PubMed  Google Scholar 

  30. 30.

    Ørstavik KH, Scheibel E, Ingerslev J, Schwartz M. Absence of correlation between X chromosome inactivation pattern and plasma concentration of factor VIII and factor IX in carriers of haemophilia A and B. Thromb Haemost. 2000;83:433–7.

    PubMed  Google Scholar 

  31. 31.

    Torres RJ, Puig JG. Skewed X inactivation in Lesh-Nyhan disease carrier females. J Hum Genet. 2017;62:1079–83.

    CAS  PubMed  Google Scholar 

  32. 32.

    Bolduc V, Chagnon P, Provost S, Dubé MP, Belisle C, Gingras M, et al. No evidence that skewing of X chromosome inactivation patterns is transmitted to offspring in humans. J Clin Invest. 2008;118:333–41.

    CAS  PubMed  Google Scholar 

  33. 33.

    Ørstavik KH. Skewed X inactivation in healthy individuals and in different diseases. Acta Paediatr Suppl. 2006;95:24–9.

    PubMed  Google Scholar 

  34. 34.

    Lacout C, Haddad E, Sabri S, Svinarchouk F, Garçon L, Capron C, et al. A defect in hematopoietic stem cell migration explains the nonrandom X-chromosome inactivation in carriers of Wiskott-Aldrich syndrome. Blood 2003;102:1282–9.

    CAS  PubMed  Google Scholar 

  35. 35.

    Migeon BR, Moser HW, Moser AB, Axelman J, Sillence D, Norum RA. Adrenoleukodystrophy: evidence for X linkage, inactivation, and selection favoring the mutant allele in heterozygous cells. Proc Natl Acad Sci USA. 1981;78:5066–70.

    CAS  PubMed  Google Scholar 

  36. 36.

    Maier EM, Kammerer S, Muntau AC, Wichers M, Braun A, Roscher AA. Symptoms in carriers of adrenoleukodystrophy relate to skewed X inactivation. Ann Neurol. 2002;52:683–8.

    CAS  PubMed  Google Scholar 

  37. 37.

    Bicocchi MP, Migeon BR, Pasino M, Lanza T, Bottini F, Boeri E, et al. Familial nonrandom inactivation linked to the X inactivation centre in heterozygotes manifesting haemophilia A. Eur J Hum Genet. 2005;13:635–40.

    CAS  PubMed  Google Scholar 

  38. 38.

    Renault NK, Pritchett SM, Howell RE, Greer WL, Sapienza C, Ørstavik KH, et al. Human X-chromosome inactivation pattern distributions fit a model of genetically influenced choice better than models of completely random choice. Eur J Hum Genet. 2013;21:1396–402.

    PubMed  PubMed Central  Google Scholar 

  39. 39.

    Orstavik KH, Orstavik RE, Schwartz M. Skewed X chromosome inactivation in a female with haemophilia B and in her non-carrier daughter: a genetic influence on X chromosome inactivation? J Med Genet. 1999;36:865–6.

    CAS  PubMed  PubMed Central  Google Scholar 

  40. 40.

    O’Donnell J, Boulton FE, Manning RA, Laffan MA. Genotype at the secret or blood group locus is a determinant of plasma von Willebrand factor level. Br J Haematol. 2002;116:350–6.

    PubMed  Google Scholar 

  41. 41.

    Sousa NC, Anicchino-Bizzacchi JM, Locatelli MF, Castro V, Barjas-Castro ML. The relationship between ABO groups and subgroups, factor VIII and von Willebrand factor. Haematologica. 2007;92:236–9.

  42. 42.

    Loomans JI, van Velzen AS, Eckhardt CL, Peters M, Mäkipernaa A, Holmstrom M, et al. Variation in baseline factor VIII concentration in a retrospective cohort of mild/moderate hemophilia A patients carrying identical F8 mutations. J Thromb Haemost. 2017;15:246–54.

    CAS  PubMed  Google Scholar 

  43. 43.

    Ay C, Thom K, Abu-Hamdeh F, Horvath B, Quehenberger P, Male C, et al. Determinants of factor VIII plasma levels in carriers of haemophilia A and in control women. Haemophilia. 2010;16:111–7.

    CAS  PubMed  Google Scholar 

  44. 44.

    Paroskie A, Gailani D, DeBaun MR, Sidonio RF Jr. A cross-sectional study of bleeding phenotype in haemophilia A carriers. Br J Haematol. 2015;170:223–8.

    CAS  PubMed  PubMed Central  Google Scholar 

  45. 45.

    Olsson A, Hellgren M, Berntorp E, Ljung R, Baghaei F. Clotting factor level is not a good predictor of bleeding in carriers of haemophilia A and B. Blood Coagul Fibrinolysis. 2014;25:471–5.

    CAS  PubMed  Google Scholar 

  46. 46.

    Merskey C, Macfarlane RG. The female carrier of haemophilia. A clinical and laboratory study. Lancet. 1951;260:487–90.

    Google Scholar 

  47. 47.

    Lusher LM, McMillan CW. Severe factor VIII and factor IX deficiency in females. Am J Med. 1978;65:637–48.

    CAS  PubMed  Google Scholar 

  48. 48.

    Mauser-Bunschoten EP, van Houwelingen JC, Sjamsoedin-Visser EJ, van Dijken PJ, Kok AJ, Sixma JJ. Bleeding symptoms in carriers of haemophilia A and B. Thromb Haemost. 1988;59:349–52.

    CAS  PubMed  Google Scholar 

  49. 49.

    Wahlberg T. Carriers and noncarriers of haemophilia A. Evaluation of bleeding symptoms registered by a self-administered questionnaire with binary (no/yes) questions. Thromb Res. 1982;25:415–22.

    CAS  PubMed  Google Scholar 

  50. 50.

    Yang MY, Ragni MV. Clinical manifestations and management of labor and delivery in women with factor IX deficiency. Haemophilia. 2004;10:483–90.

    CAS  PubMed  Google Scholar 

  51. 51.

    Di Michele DM, Gibb C, Lefkowitz JM, Ni Q, Gerber LM, Ganguly A. Severe and moderate haemophilia A and B in US females. Haemophilia. 2014;20:e136–43.

    PubMed  Google Scholar 

  52. 52.

    Paroskie A, Oso O, Almassi B, DeBaun MR, Sidonio RF Jr. Both hemophilia health care providers and hemophilia a carriers report that carriers have excessive bleeding. J Pediatr Hematol Oncol. 2014;36:e224–30.

    PubMed  PubMed Central  Google Scholar 

  53. 53.

    Raso S, Lambert C, Boban A, Napolitano M, Siragusa S, Hermans C. Can we compare haemophilia carriers with clotting factor deficiency to male patients with mild haemophilia? Haemophilia. 2020;26:117–21.

    CAS  PubMed  Google Scholar 

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The authors thank Dr Luigi Flaminio Ghilardini for help with the figures.

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Correspondence to Isabella Garagiola.

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ES is a member of advisory committees (Sobi, NovoNordisk, Roche, Shire, Bayer, Kedrion, Grifols, Pfizer) and speaker bureaus (Octapharma, Kedrion, Grifols, Bayer, Roche, Shire, Bioverativ, Sobi, NovoNordisk, Pfizer, CSL Behring). FP has received honoraria for participating as a speaker at satellite symposia organised by Bioverativ, Grifols, Roche, Sanofi, Sobi, Spark and Takeda. FP reports participation on the advisory boards of Sanofi and Sobi.

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Garagiola, I., Mortarino, M., Siboni, S.M. et al. X Chromosome inactivation: a modifier of factor VIII and IX plasma levels and bleeding phenotype in Haemophilia carriers. Eur J Hum Genet 29, 241–249 (2021).

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