Only a few cases were described on genetically closed Devon Rex cats (common progenitor) in the 80's in the United Kingdom. Since that moment, no other case of this disorder was reported. This is an inherited autosomal disease, poorly documented (only one study in 1990).
The affected cats present a marked reduction in factors II, VII, IX and X (II, IX and X <20%; VII <50% of values for pooled normal cat plasma).
Coagulation tests reveal that prothrombin times (PT) and activated partial thromboplastin times (APTT) are substantially prolonged, whereas platelet counts and fibrinogen values are normal.
Clinically, cats may have spontaneous hemorrhages of joints, cavities (thorax), bladder, sublumbar area.etc. which can lead to lethargy, respiratory difficulties or lameness. Subcutaneous or conjunctival hematoma can be noticed. But also excessive seepage of blood can be observed from venipuncture sites or surgical sites.
Oral administration of vitamin K1 (everyday at the beginning, then twice a week) results in normalization of clotting factors concentration. Depending on blood loss, a blood transfusion may be necessary.