We maintain websites for genetic variants in the human coagulation factors F7, F8, F9 and F11 as a service for clinicians and biochemists.

F9 Variants

Haemophilia B is caused by variants (mutations) in the F9 gene which codes for coagulation factor IX. There are currently 1094 unique variants in the F9 gene compiled within this database corresponding to 3713 individual cases.


Citing us

If you find this website useful, please reference our publications:
Saunders, R. E., O’Connell, N. M., Lee, C. A., Perry, D. J. & Perkins, S. J. (2005) The factor XI deficiency database: an interactive web database of mutations, phenotypes and structural analysis tools. Human Mutation, 26, 192-198. PM:16086308

Rallapalli, P.M., Kemball-Cook, G., Tuddenham, E.G., Gomez, K. & Perkins, S.J. (2013) An interactive mutation database for human coagulation factor IX provides novel insights into the phenotypes and genetics of haemophilia B. J.Thromb.Haemost. 11, 1329-1340 PM:23617593

What can you do in this database?

You can search for all the mutations reported in the F9 gene prior to the database release date. You can look in the database for all the sequence, structural and statistical information for the mutations. You can also submit new mutations/variants and contribute to the genetic services provided through this database.

For easy navigation across the website, please click for the Site Map.

Simple Amino Acid Search

Exon and Intron based search

    Codon/Amino-acid numbering: HGVS and Legacy  


    Classification of Variant Phenotype (Severity):  


    Have you or someone you know been diagnosed with haemophilia B?  


    Acknowledgements and Disclaimer  


    Latest Release- Version 2.0 ( January 2021 )  

The information contained on this web site is provided for research purposes only. All information and content on this web site are protected by UCL copyright. All rights are reserved.

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Factor IX Variant Database