Inherited Feline Blood Clotting Disorders: Genetic Testing and Breeder Practices

Most professional breeders of pedigree domestic cats screen their cats for inherited diseases and traits.

- Lucy Drury

Several veterinary genetic laboratories, both academic and commercial, offer multi-test profiles of a few dozen of the most popular genetic screens to more than 50. Several labs have added to their feline genetic screening profile two inherited blood clotting disorders: Factor IX (Christmas Factor) deficiency and Factor XII (Hageman) deficiency.

Why are these important, and what should a breeder do if one of their cats is found to carry one of these traits? Before we answer those questions, a brief discussion of blood clotting mechanisms and current laboratory screening tests of the efficiency of those mechanisms is necessary.

The Miracle of Blood Clotting

We take it for granted. We are playing with Fluffy and his favorite toy, and our hand gets in the way of that paw batting at the toy. We yelp a little, look at the scratch oozing a tiny bit of blood, then wipe it off with the nearest available absorbent form of paper. Already stopped bleeding, we think to ourselves. We shake it off and think to ourselves that Fluffy is overdue for a nail trim.

What we fail to appreciate is that not only does Fluffy need a nail trim, but those claws of his set off a cascade of biochemical reactions that has saved our life, time and again, and we don't even realize it. That process is more formally called hemostasis.¹ Hemostasis is essentially the same process in both humans and felines.