Research Communications of the 24th ECVIM-CA Congress

We report here on the discovery of FVII deficiency in Welsh Springer Spaniels (WSS) in Finland based upon a novel screening panel for~100 known mutations underlying inherited disorders in different canine breeds (www.mydogdna.com). Among 31 WSS initially tested, 12 were heterozygously (39%), and 1 homozygously affected for the same FVII mutation, which was confirmed by sequencing in all dogs. In order to determine whether the mutation causes FVII deficiency also in this breed, we recruited 6 littermates and their mother. None of these WSS had shown an increased hemorrhagic tendency, but affecteds bled excessively following blood collection. We found that the 3 homozygous affected dogs of the litter exhibited markedly prolonged prothrombin time but normal partial thromboplastin time. They also had drastically reduced FVII activities but normal to high FVIII and FIX activities compared to their littermate controls. The 3 heterozygous carriers tested did not show any prolongations in their prothrombin time, but had half normal FVII activity.