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Hereditary factor IX deficiency disease

From SNPedia

Hereditary Factor IX Deficiency Disease, also called Factor IX deficiency is an X-linked blood clotting disorder caused by a mutation of the F9 or Factor IX gene. This deficiency results in Hemophilia B, also known as Christmas Disease, which is the second-most common form of hemophilia after Hemophilia A. [1].

More than 900 alterations in the F9 gene have been identified. The most common alterations are due to SNPs while a smaller percentage of alterations are due to deletions or insertions of multiple base pairs, or rearrangements of DNA segments within the gene. [2]

Rare mutations in the F9 gene can cause cause a hypersensitivity to warfarin. These mutations do not cause hemophilia B, however people with these genetic changes have bleeding problems if they are treated with warfarin as warfarin reduces the amount of coagulation factor IX to very low levels. This prevents the blood from clotting normally and can lead to recurrent, severe bleeding problems. [3]


[PMID 19286883OA-icon.png] The F9 Malmö variant of coagulation factor IX, recognized by rs6048, has been associated with protection against deep vein thrombosis. This variant has not been reported to be associated with hemophilia B. [4]


[PMID 19846852OA-icon.png] A rare gain of function mutation (R338L) Rs137852283, also known as Factor IX Padua, results in hyperfunctional factor IX and has been associated with thrombophilia and deep vein thrombosis. While the level of this mutant factor IX protein in plasma was normal, the clotting activity of factor IX from the proband was approximately eight times the normal level, and resulted in elevated clotting activity.