A novel missense mutation responsible for factor VII deficiency in research Beagle colonies.
BACKGROUND
Canine factor VII (cFVII) deficiency, an autosomal recessive trait originally identified in research Beagles, is associated with a mild to moderate bleeding tendency.


OBJECTIVE
Our aim was to identify and characterize the mutation causing cFVII deficiency.


METHODS
In order to sequence the coding regions of the cFVII gene, we cloned the cFVII cDNA. Genomic DNA and plasma from FVII-deficient Beagles and obligate carriers were utilized.


RESULTS
In all FVII-deficient dogs, we identified a single causative G to A missense mutation in exon 5, encoding the second epidermal growth factor-like domain, resulting in substitution of glycine 96 by glutamic acid, with plasma FVII coagulant activity of <or = 4% in affected Beagles. In vitro expression indicated that the majority (96%) of cFVII-G96E protein was retained intracellularly. In addition, analysis of purified recombinant wild-type and mutant cFVII proteins demonstrated reduced activity of the mutant (< 2%) compared with wild-type. Rotational thromboelastometry revealed a severe impairment of clotting activity in affected Beagles, and heterozygotes also exhibited changes in coagulation-based assays. Using a mutation-specific polymerase chain reaction/restriction digest that allows rapid identification of the G96E mutation, we surveyed a US research Beagle colony and identified a mutant allelic frequency of 31%.


CONCLUSIONS
We have identified a single causative mutation for cFVII deficiency that may have implications for pharmacotoxicologic research, because reduced FVII coagulant activity may alter hemostatic and/or cardiovascular endpoints in this commonly used animal species.
Callan
M B
MB
School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA.
Aljamali
M N
MN
Margaritis
P
P
Griot-Wenk
M E
ME
Pollak
E S
ES
Werner
P
P
Giger
U
U
High
K A
KA
D000595:Amino Acid Sequence; D000818:Animals; D001777:Blood Coagulation; D002460:Cell Line; D003001:Cloning, Molecular; D004252:DNA Mutational Analysis; D004283:Dog Diseases / Q000097:blood / Q000235:genetics*; D004285:Dogs; D005167:Factor VII / Q000235:genetics* / Q000378:metabolism; D005168:Factor VII Deficiency / Q000097:blood / Q000235:genetics* / Q000662:veterinary*; D005787:Gene Frequency; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D008969:Molecular Sequence Data; D020125:Mutation, Missense; D016133:Polymerase Chain Reaction; D011517:Prothrombin Time; D011994:Recombinant Proteins / Q000378:metabolism; D016415:Sequence Alignment; D020539:Sequence Analysis, Protein; D013916:Thrombelastography; D014162:Transfection
D011994:Recombinant Proteins; D005167:Factor VII