We maintain websites for genetic variants in the human coagulation factors F5, F7, F8, F9, F10, and F11 as a service for clinicians and biochemists. This F9 website is updated (March 2023) with 1692 variants, in place of the 1113 variants in its predecessor from 2013.

F9 Variants

Haemophilia B is caused by variants (mutations) in the F9 gene which codes for coagulation factor IX. There are currently 1692 unique variants in the F9 gene compiled within this database corresponding to 5358 individual cases.

Citing us

If you find this website useful, please reference our publications:

Xu, Z., Spencer, H. J., Harris, V. A. & Perkins, S. J. (2023) An updated interactive database for 1692 genetic variants in Factor IX provides new insights into Haemophilia B. J. Thromb. Haemost. 21, 1164-1176 PM:36787808

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

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

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 2.1 ( July 2022 )  

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