# Novel missense mutation in the coagulation factor IX catalytic domain associated with severe haemophilia B- Factor $IX_{Delhi}$

Mahajan, A and Sharma, A and Chavali, S and Kabra, M and Chowdhury, MR and Srinivasan, N and Bharadwaj, D (2004) Novel missense mutation in the coagulation factor IX catalytic domain associated with severe haemophilia B- Factor $IX_{Delhi}$. In: Haemophilia, 10 (5). pp. 550-552.

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## Abstract

Factor IX is a vitamin K-dependent serine protease, which exists as a zymogen in the blood. On activation to factor IXa, by factor XIa or tissue factor factor VIIa complex, it forms tenase complex with factor VIIIa, in the presence of $Ca^{\mathrm{2+}}$. This tenase complex enzymatically converts factor X to factor Xa, thereby bringing about the coagulation cascade. Mutations in factor IX gene have been shown to cause haemophilia B, which is inherited as an X-linked recessive disorder. Herein we report a novel missense mutation at the nucleotide position 30829-T > A in the exon 8 of factor IX gene. This transversion leads to the substitution of histidine 236 to glutamine. This resulting abnormal protein has been named factor $IX_{Delhi}$. Molecular modelling was performed to predict the molecular pathology of this mutation. We predict that this change in the catalytic domain may affect the surface loop that accommodates $Ca^{\mathrm{2+}}$, thereby leading to severe bleeding disorder.

Item Type: Journal Article Copyright of this article belongs to John Wiley and Sons. Division of Biological Sciences > Molecular Biophysics Unit 02 Dec 2004 18 Jan 2012 06:30 http://eprints.iisc.ernet.in/id/eprint/2342