CASE REPORT
Classic Hemophilia (Hemophilia A) in a Family of Collies D. M. BENN, P. A. GENTRY AND I. B. JOHNSTONE*
Introduction Inherited bleeding disorders are known to occur in many breeds of dogs (2, 5, 8). Hemophilia A (Factor VIII deficiency) is not only one of the most clinically severe bleeding disorders but is also one of the most widely recognized congenital coagulation defects. As early as 1963, Hemophilia A was reported in the Collie breed (7). Recently we have found four male collies from three separate but related litters to be suffering from Hemophilia A, indicating that this coagulation disorder is being transmitted in a line of Canadian bred Collies. The purpose of this report is to describe the clinical symptoms, laboratory profiles and family pedigree of these dogs and to discuss the role of the veterinarian in attempting to ensure that the disorder is contained by counselling owners and breeders.
nary College with a history of intermittent lameness, hematuria, and intestinal bleeding of over two weeks duration. The pup was two months old when the breeder first noticed the shifting lameness. There was no knowledge of trauma or evidence of joint swelling at any time. Two weeks prior to presentation a large swelling developed in the left periorbital area. This swelling had not significantly decreased in size at the time of presentation. On physical examination, the pup was in good condition. The body temperature was 38.4°C, pulse was 140 beats per minute and the respiratory rate was 36 per minute. A fluctuant swelling, 6cm in diameter, was present caudad to the lateral canthus of the left eye. Aspiration of this periorbital swelling revealed large numbers of red blood cells and serum. Hind quarter stiffness was apparent at this time. Treatment was not necessary and this pup was subsequently donated to our hemophiliac colony.
Clinical Histories, Findings and Therapy Case A: On September 10, 1976 a six month old Collie male was referred to the Ontario Veterinary College for examination. During the week prior to presentation, the owners had noticed intermittent oral bleeding and the sudden appearance of two large fluctuant swellings in the left thoracic region. At the time of presentation, this dog was in good body condition. Body temperature was 39.5°C and the pulse was 160 beats per minute. The oral and conjunctival mucous membranes were pale and there was an oral ulcer in the region of the left carnesial tooth that was oozing blood. Two discrete, firm swellings, 7 cm x 3 cm, were also present in the left thoracic area. No other physical abnormalities were noted. Aspiration of the thoracic swellings revealed clotted blood and serum. No treatment was instituted and the dog was euthanized one week later.
Case C: A three month old male Collie, littermate to Case B, was also presented to the Ontario Veterinary College on October 13, 1976. In the preceding month a very firm swelling had appeared over his frontal sinus. This swelling was lanced and upon finding it to be a hematoma, the incision was sutured. Healing proceeded very slowly with frequent rebleeding from that site. Since that time, another swelling developed below the right eye but resolved before presentation. On physical examination the pup was in good body condition with a temperature of 38.5°C, pulse of 136 beats per minute and respiratory rate of 40 per minute. The 6 cm incision on the frontal sinus was healing and the skin sutures were still in place. No other physical abnormalities were noticed at that time and treatment was not necessary. This pup was also donated to the hemophiliac colony. The history of the remaining eight pups in the litter was obtained from the breeder. One female was born dead, one male died within two hours of birth, while another male died at two days of age. Two females and two males had experienced no problems and appeared to be healthy. The remaining littermate was a male, who at two and a half months of age, became depressed and listless and within a few hours was tetraplegic. Blood oozed from his ears and subcutaneous swellings developed over his right neck and shoulder region. Autopsy revealed clots of blood within the abdominal and thoracic cavities and extensive subcutaneous hematomas.
Case B: On October 13, 1976 a three month old male Collie was presented to the Ontario Veteri-
Case D: A three and a half month old Collie was presented to the Ontario Veterinary College on
*Department of Clinical Studies (Benn) and Department of Biomedical Sciences (Gentry and Johnstone), Ontario Veterinary College, University of Guelph, Guelph, Ontario NIG 2W1.
Can. vet. J. 19: 221-225 (August 1978)
221
TABLE I HEMOGRAMS OF FOUR COLLIES WITH HEMOPHILIA A
RBC x 106/mm3 Hb x g/lOOml PCV %
WBC/mm3 Platelets/mm3 'Adult values (9).
Case A
Case B
Case C
Case D
4.55 10.1 29.5
6.34 12.8 37.1
6.33 13.4 37.7
18,700 650,000
18,400 750,000
16,900 960,000
5.15 11.1 34.2 10,000
April 14, 1977 with a history of ataxia and lameness of one month's duration. During the preceding two days, the pup had developed a moist, harsh cough. The pup experienced posterior paresis and a proprioceptive deficit of his hind limbs at nine weeks of age shortly after playing with another dog. No radiographic abnormalities were detected and the dog was treated with corticosteroids with no apparent response. Two weeks later, he became lame on his right forelimb with soft tissue swelling on the shoulder region. Once again, no radiographic changes were seen. On presentation this dog was in good physical condition with a temperature of 39.0°C and pulse and respiratory rates within normal range. The oral and conjunctival mucous membranes were pale but capillary refill was visible. A firm swelling was present in the upper right humeral region and the pup was lame. A persistent, harsh, moist cough was heard but lung sounds were normal. Radiographic studies revealed a pulmonary hilar edematous pattern and tracheal stenosis. Minimal periosteal reaction was apparent on the right humerus at the midshaft. This pup was euthanized on request from the owners.
Laboratory Findings The hemograms on blood samples obtained from the four dogs at the time of their presentation to the Clinic are shown in Table I. Case A was mildly anemic when admitted but had a normal hemogram two days after admission. In Cases B and C, the hemograms appeared normal. In Case D, the red cell count, hemoglobin concentration and packed cell volume, though slightly below normal adult values (9), were considered to be normal in the three and one half month old pup. Thrombocytosis was evident in Cases A, B and C. However, within 30 days, the platelet counts of Cases B and C were within the normal range. The initial coagulation screening on each of these dogs revealed a prolonged activated partial thromboplastin time (APTT) and a normal onestage prothrombin time (OSPT). The results indicated that the dogs appeared to have a problem with the intrinsic coagulation mechanism and that the extrinsic mechanism was functionally competent (4). Specific coagulation factor activity
222
Normal Range' 5.5-8.5 12-18 37-55 6,000-17,000
200,000-500,000
showed that each of these animals had very low Factor VIII procoagulant (F VIIIAHF) activity. The preliminary findings when considered along with clinical history and pedigree information indicated that the dogs had either Hemophilia A (Factor VIIIAHF) or Von Willebrand's disease. To assist in the diagnosis, further testing was performed on fresh blood samples from each of the dogs. The bitch and litter-mates of two of the affected dogs (Cases B and C) were also tested for coagulation competence. The pedigree showing the relationships of all the dogs tested is shown in Figure 1. The coagulation profiles for each of the dogs are shown in Table II. Prolonged PTT times were found for each of the four males in which clinical evidence of bleeding had been noted (Cases A-D). Confirming the preliminary findings, the F VIIIAHF activity level for each of these dogs was extremely low, being less than 1% ofnormal in A, B and C and 5% of normal in D. The other two males tested (dogs F and G) had normal PTT times and normal F VIIIAHF activity. Although the PTT results of the two females tested (E and H) were normal, the specific F VIIIAHF assay results were below normal being 36% and 42% respectively. The one-stage prothrombin time, fibrinogen, F VII and F IX values were all within the normal range for this laboratory in all the dogs studied. Von Willebrand factor (F VIIIvwF) activity was assessed on samples from three of the males with low F VIIIAHF values (dogs A, B and C) by the ristocetin platelet aggregation test (10). Factor VIIIVwF is the component of the Factor VIII molecular complex necessary for proper platelet activity. The F VIIIVwF activities in dogs A, B and C were 70, 93 and 95% of normal respectively. Factor VIII antigen levels were determined by crossed-immunolectrophoresis on agarose (1) and were found to be within the normal range. The clinical history, laboratory findings and pedigree indicate that the hemorrhagic problem encountered in these dogs is Hemophilia A (Classic hemophilia, Factor VIIIAHF deficiency). The female carriers of the disorder can transmit the defect to their offspring on the affected X chromosome. Only male animals are usually severely affected by the disorder and exhibit
I
A -
-
-
-
.-
-
I I
b
I %.
D FIGURE 1. Illustrates the known ( ) and suspected (----) pedigrees of the dogs. * Affected male O Carrier female 1* @ Pups died at birth or shortly afterwards El(® Animals not available for testing Ol Normal male
clinical symptoms. Female dogs with severe Hemophilia A can result from the breeding of an affected male with a carrier or affected female. This however is not common. The pedigree profile (Figure 1) shows the typical pattern of inheritance of Hemophilia A. Bitch E, a carrier of the disorder, transmitted the disease to at least two of her male offspring, while at least one of her female pups appeared also to be a carrier of the disorder. Although it has not been possible to obtain samples from bitch I for laboratory testing this bitch is presumed to be a carrier having produced at least one affected male and one carrier female by separate matings with different males.
daughters have the potential of being carriers of the trait. Carriers have a partial deficiency of Factor VIIIAHF but are not clinically affected. Hemophilia A carriers can be detected by specific Factor VIIIAHF assays as their Factor VIII activity is about 50o of normal (6). Because of biological variation between dogs and between samples obtained from the same dog, it can be difficult to separate a "high" carrier from a "low" normal. In this situation the results of test matings are an important aid in confirming the carrier status of a bitch. On the other hand, hemophilic dogs fall into one of three general categories: mild, 5-20o; moderate, 1-5%; severe with less than 1% Factor VIIIAHF activity. The severity of the condition is directly related to the amount of Factor VIIIAHF activity, while a minimum level of twenty percent is necessary for normal hemostasis (2). Factor VIIIAHF deficiency can be detected by the presence of a prolonged partial thromboplas-
Discussion Hemophilia A is an X-linked recessive coagulation disorder in which Factor VIIIAHF activity is reduced. The disease is transmitted by carrier females and is manifested as hemophilia in approximately 50% of their sons, while 50o of their
TABLE II COAGULATION PROFILES
Animal
Normal, Test
PTT (sec) OSPT (sec) Fibrinogen (mg/dl) F VIIb FVIIb F IXb
Case A Case B Case C Case D Case E Case F Case G Case H 76.1 17.5 320 153
Classic Hemophilia (Hemophilia A) in a Family of Collies D. M. BENN, P. A. GENTRY AND I. B. JOHNSTONE*
Introduction Inherited bleeding disorders are known to occur in many breeds of dogs (2, 5, 8). Hemophilia A (Factor VIII deficiency) is not only one of the most clinically severe bleeding disorders but is also one of the most widely recognized congenital coagulation defects. As early as 1963, Hemophilia A was reported in the Collie breed (7). Recently we have found four male collies from three separate but related litters to be suffering from Hemophilia A, indicating that this coagulation disorder is being transmitted in a line of Canadian bred Collies. The purpose of this report is to describe the clinical symptoms, laboratory profiles and family pedigree of these dogs and to discuss the role of the veterinarian in attempting to ensure that the disorder is contained by counselling owners and breeders.
nary College with a history of intermittent lameness, hematuria, and intestinal bleeding of over two weeks duration. The pup was two months old when the breeder first noticed the shifting lameness. There was no knowledge of trauma or evidence of joint swelling at any time. Two weeks prior to presentation a large swelling developed in the left periorbital area. This swelling had not significantly decreased in size at the time of presentation. On physical examination, the pup was in good condition. The body temperature was 38.4°C, pulse was 140 beats per minute and the respiratory rate was 36 per minute. A fluctuant swelling, 6cm in diameter, was present caudad to the lateral canthus of the left eye. Aspiration of this periorbital swelling revealed large numbers of red blood cells and serum. Hind quarter stiffness was apparent at this time. Treatment was not necessary and this pup was subsequently donated to our hemophiliac colony.
Clinical Histories, Findings and Therapy Case A: On September 10, 1976 a six month old Collie male was referred to the Ontario Veterinary College for examination. During the week prior to presentation, the owners had noticed intermittent oral bleeding and the sudden appearance of two large fluctuant swellings in the left thoracic region. At the time of presentation, this dog was in good body condition. Body temperature was 39.5°C and the pulse was 160 beats per minute. The oral and conjunctival mucous membranes were pale and there was an oral ulcer in the region of the left carnesial tooth that was oozing blood. Two discrete, firm swellings, 7 cm x 3 cm, were also present in the left thoracic area. No other physical abnormalities were noted. Aspiration of the thoracic swellings revealed clotted blood and serum. No treatment was instituted and the dog was euthanized one week later.
Case C: A three month old male Collie, littermate to Case B, was also presented to the Ontario Veterinary College on October 13, 1976. In the preceding month a very firm swelling had appeared over his frontal sinus. This swelling was lanced and upon finding it to be a hematoma, the incision was sutured. Healing proceeded very slowly with frequent rebleeding from that site. Since that time, another swelling developed below the right eye but resolved before presentation. On physical examination the pup was in good body condition with a temperature of 38.5°C, pulse of 136 beats per minute and respiratory rate of 40 per minute. The 6 cm incision on the frontal sinus was healing and the skin sutures were still in place. No other physical abnormalities were noticed at that time and treatment was not necessary. This pup was also donated to the hemophiliac colony. The history of the remaining eight pups in the litter was obtained from the breeder. One female was born dead, one male died within two hours of birth, while another male died at two days of age. Two females and two males had experienced no problems and appeared to be healthy. The remaining littermate was a male, who at two and a half months of age, became depressed and listless and within a few hours was tetraplegic. Blood oozed from his ears and subcutaneous swellings developed over his right neck and shoulder region. Autopsy revealed clots of blood within the abdominal and thoracic cavities and extensive subcutaneous hematomas.
Case B: On October 13, 1976 a three month old male Collie was presented to the Ontario Veteri-
Case D: A three and a half month old Collie was presented to the Ontario Veterinary College on
*Department of Clinical Studies (Benn) and Department of Biomedical Sciences (Gentry and Johnstone), Ontario Veterinary College, University of Guelph, Guelph, Ontario NIG 2W1.
Can. vet. J. 19: 221-225 (August 1978)
221
TABLE I HEMOGRAMS OF FOUR COLLIES WITH HEMOPHILIA A
RBC x 106/mm3 Hb x g/lOOml PCV %
WBC/mm3 Platelets/mm3 'Adult values (9).
Case A
Case B
Case C
Case D
4.55 10.1 29.5
6.34 12.8 37.1
6.33 13.4 37.7
18,700 650,000
18,400 750,000
16,900 960,000
5.15 11.1 34.2 10,000
April 14, 1977 with a history of ataxia and lameness of one month's duration. During the preceding two days, the pup had developed a moist, harsh cough. The pup experienced posterior paresis and a proprioceptive deficit of his hind limbs at nine weeks of age shortly after playing with another dog. No radiographic abnormalities were detected and the dog was treated with corticosteroids with no apparent response. Two weeks later, he became lame on his right forelimb with soft tissue swelling on the shoulder region. Once again, no radiographic changes were seen. On presentation this dog was in good physical condition with a temperature of 39.0°C and pulse and respiratory rates within normal range. The oral and conjunctival mucous membranes were pale but capillary refill was visible. A firm swelling was present in the upper right humeral region and the pup was lame. A persistent, harsh, moist cough was heard but lung sounds were normal. Radiographic studies revealed a pulmonary hilar edematous pattern and tracheal stenosis. Minimal periosteal reaction was apparent on the right humerus at the midshaft. This pup was euthanized on request from the owners.
Laboratory Findings The hemograms on blood samples obtained from the four dogs at the time of their presentation to the Clinic are shown in Table I. Case A was mildly anemic when admitted but had a normal hemogram two days after admission. In Cases B and C, the hemograms appeared normal. In Case D, the red cell count, hemoglobin concentration and packed cell volume, though slightly below normal adult values (9), were considered to be normal in the three and one half month old pup. Thrombocytosis was evident in Cases A, B and C. However, within 30 days, the platelet counts of Cases B and C were within the normal range. The initial coagulation screening on each of these dogs revealed a prolonged activated partial thromboplastin time (APTT) and a normal onestage prothrombin time (OSPT). The results indicated that the dogs appeared to have a problem with the intrinsic coagulation mechanism and that the extrinsic mechanism was functionally competent (4). Specific coagulation factor activity
222
Normal Range' 5.5-8.5 12-18 37-55 6,000-17,000
200,000-500,000
showed that each of these animals had very low Factor VIII procoagulant (F VIIIAHF) activity. The preliminary findings when considered along with clinical history and pedigree information indicated that the dogs had either Hemophilia A (Factor VIIIAHF) or Von Willebrand's disease. To assist in the diagnosis, further testing was performed on fresh blood samples from each of the dogs. The bitch and litter-mates of two of the affected dogs (Cases B and C) were also tested for coagulation competence. The pedigree showing the relationships of all the dogs tested is shown in Figure 1. The coagulation profiles for each of the dogs are shown in Table II. Prolonged PTT times were found for each of the four males in which clinical evidence of bleeding had been noted (Cases A-D). Confirming the preliminary findings, the F VIIIAHF activity level for each of these dogs was extremely low, being less than 1% ofnormal in A, B and C and 5% of normal in D. The other two males tested (dogs F and G) had normal PTT times and normal F VIIIAHF activity. Although the PTT results of the two females tested (E and H) were normal, the specific F VIIIAHF assay results were below normal being 36% and 42% respectively. The one-stage prothrombin time, fibrinogen, F VII and F IX values were all within the normal range for this laboratory in all the dogs studied. Von Willebrand factor (F VIIIvwF) activity was assessed on samples from three of the males with low F VIIIAHF values (dogs A, B and C) by the ristocetin platelet aggregation test (10). Factor VIIIVwF is the component of the Factor VIII molecular complex necessary for proper platelet activity. The F VIIIVwF activities in dogs A, B and C were 70, 93 and 95% of normal respectively. Factor VIII antigen levels were determined by crossed-immunolectrophoresis on agarose (1) and were found to be within the normal range. The clinical history, laboratory findings and pedigree indicate that the hemorrhagic problem encountered in these dogs is Hemophilia A (Classic hemophilia, Factor VIIIAHF deficiency). The female carriers of the disorder can transmit the defect to their offspring on the affected X chromosome. Only male animals are usually severely affected by the disorder and exhibit
I
A -
-
-
-
.-
-
I I
b
I %.
D FIGURE 1. Illustrates the known ( ) and suspected (----) pedigrees of the dogs. * Affected male O Carrier female 1* @ Pups died at birth or shortly afterwards El(® Animals not available for testing Ol Normal male
clinical symptoms. Female dogs with severe Hemophilia A can result from the breeding of an affected male with a carrier or affected female. This however is not common. The pedigree profile (Figure 1) shows the typical pattern of inheritance of Hemophilia A. Bitch E, a carrier of the disorder, transmitted the disease to at least two of her male offspring, while at least one of her female pups appeared also to be a carrier of the disorder. Although it has not been possible to obtain samples from bitch I for laboratory testing this bitch is presumed to be a carrier having produced at least one affected male and one carrier female by separate matings with different males.
daughters have the potential of being carriers of the trait. Carriers have a partial deficiency of Factor VIIIAHF but are not clinically affected. Hemophilia A carriers can be detected by specific Factor VIIIAHF assays as their Factor VIII activity is about 50o of normal (6). Because of biological variation between dogs and between samples obtained from the same dog, it can be difficult to separate a "high" carrier from a "low" normal. In this situation the results of test matings are an important aid in confirming the carrier status of a bitch. On the other hand, hemophilic dogs fall into one of three general categories: mild, 5-20o; moderate, 1-5%; severe with less than 1% Factor VIIIAHF activity. The severity of the condition is directly related to the amount of Factor VIIIAHF activity, while a minimum level of twenty percent is necessary for normal hemostasis (2). Factor VIIIAHF deficiency can be detected by the presence of a prolonged partial thromboplas-
Discussion Hemophilia A is an X-linked recessive coagulation disorder in which Factor VIIIAHF activity is reduced. The disease is transmitted by carrier females and is manifested as hemophilia in approximately 50% of their sons, while 50o of their
TABLE II COAGULATION PROFILES
Animal
Normal, Test
PTT (sec) OSPT (sec) Fibrinogen (mg/dl) F VIIb FVIIb F IXb
Case A Case B Case C Case D Case E Case F Case G Case H 76.1 17.5 320 153
