Hemophilia A and hemophilia B in a family of French bulldogs.

A congenital coagulation defect was suspected in 10 male French bulldogs, independently referred to the Small Animal Clinic of the Utrecht State University by private pet owners from all over the country. The cases are described in this report. Coagulation studies, performed in 8 of these dogs, revealed a factor VIII (anti-hemophilic globulin) deficiency in 5, and a factor IX (Christmas factor) deficiency in 3 propositi. A pedigree analysis revealed that all of the 10 propositi were lineal descendants, in the female line, of one and the same female ancestor. An inquiry by letter among the owners of 210 male descendants, in the female line, of this common ancestor revealed hemorrhagic episodes in at least another 10 male offspirng. The presence of a large number of carriers can be expected among the French bulldog population in the Netherlands, since the officially registered female offspring in the female line of the ancestor bitch, comprised over 170 dogs as of January, 1971. The possible mechanisms responsible for the simultaneous occurrence of hemophilia A and B in one canine family are discussed.