Combined factors IX and XII deficiencies in a family of cats.

Combined factors IX and XII deficiencies were detected in a family of cats in which 2 male kittens had bleeding diathesis. The combination of factors IX and XII deficiencies in one male kitten did not appear to exacerbate bleeding when compared with a sole deficiency of factor IX in its male sibling. Neutering of carrier females and affected males was recommended. Blood transfusions before castration of affected males was advised.