Other names: Christmas disease, Factor IX deficiency
Gene affected: F9
Transmission: Recessive, linked to the X chromosome
Mutation: CanFam3.1 X g.109532018G>A c.1253G>A

* In hereditary genetic diseases linked to the X chromosome, the following rules apply:
-For a recessive disease, the male is affected (at risk for developing the disease) even if he has only one copy of the mutation.
-Male-to-male transmission doesn't exist, since a male never passes on his X chromosome to his sons.
-All females of an affected male will inherit the mutant gene.
-Females who are carriers have a 50% chance of passing the mutant gene to their sons and daughters.

OMIA link: 000438-9615

Breeds suitable for testing: Cairn Terrier

References:
Evans JP, Brinkhous KM, Brayer GD, Reisner HM, High KA. Canine hemophilia B resulting from a point mutation with unusual consequences. Proc Natl Acad Sci U S A. 1989 Dec; 86(24):10095-9. [PubMed: 2481310]