Glanzmanns Thrombasthenia in Otterhounds
A bleeding disorder called Thrombasthenic thrombopathia was first described in
Otterhounds in 1967.1 Affected dogs had mucosal bleeding and prolonged bleeding times.
Platelet aggregation responses were minimal or lacking and clot retraction was severely impaired.
Abnormal clot retraction tests and platelet aggregation studies were used as screening tests in an
effort to eliminate Thrombasthenic thrombopathia from the Otterhound breed in the 70s and
80s. As a result of this testing, it was thought that the platelet disorder had been largely
eliminated from the breed, however, in the early 1990s, descendents of the dogs originally
described with Thrombasthenic thrombopathia were identified with platelet dysfunction. Because
Thrombasthenic thrombopathia closely resembled the Glanzmanns thrombasthenia platelet
disorder that had been described in Great Pyrenees dogs in 1996 and 2000,2-3 molecular studies
were begun in Dr. Boudreauxs laboratory to determine whether a mutation could be found that
caused Thrombasthenic thrombopathia in Otterhounds. Blood samples were collected from the
affected Otterhounds identified by Dr. James Catalfamo at Cornell University in the early 1990s.
As a result of this work, it was determined that Otterhound Thrombasthenic thrombopathia was
identical to Type I Glanzmanns thrombasthenia (GT),4 based on the finding that affected
Otterhounds had a mutation in the gene encoding for platelet glycoprotein IIb (mutations in either
of the genes encoding for glycoproteins IIb or IIIa have been documented to cause GT in human
beings). Although Otterhounds and Great Pyrenees both have mutations in the gene encoding for
platelet glycoprotein IIb, and therefore both breeds are affected with GT, the mutations that cause
the disease are different for the two breeds. The mutation causing GT in Otterhounds is in Exon
12 while the mutation causing GT in Great Pyrenees is in Exon 13.
Type I GT has been recognized for many years in humans and is due to a
congenital/inherited membrane defect in platelets. Platelets are small, circulating cytoplasmic
fragments that are the first line of defense in stopping the flow of blood from injured blood
vessels. An important aspect of platelet function is their ability to stick to each other and plug
holes in damaged vessels until blood clotting and tissue repair can occur. The platelets of people
and dogs with Type I GT are defective in their ability to stick to each other. Therefore, these
individuals are at increased risk for spontaneous hemorrhage and they are also at high risk for
excessive hemorrhage as a result of injury or surgery. The type of spontaneous bleeding that
occurs with GT includes excessive gingival bleeding during tooth eruption, nose bleeds, and
superficial skin bleeds. Young dogs less than 18 months of age are especially prone to excessive,
By using DNA testing, affected and carrier animals can now be identified by simply
submitting a blood sample through the mail. By using DNA testing, carriers can be accurately
identified before breeding to avoid spreading the mutation and to avoid producing affected
puppies. Carrier detection is vital in controlling spread of inherited defects and DNA testing is
the only reliable method of detecting these animals.
1. Dodds WJ. Familial canine thrombocytopathy. Thromb Diath Haemorrh Suppl 26:241-248, 1967.
2. Boudreaux MK, Kvam K, Dillon AR, Bourne C, Scott M, Schwartz KA, Toivio-Kinnucan M. Type I
Glanzmanns Thrombasthenia in a Great Pyrenees Dog. Veterinary Pathology 33:503-511, 1996.
3. Lipscomb DL, Bourne C, Boudreaux MK: Two genetic defects in alpha IIb are associated with Type I
GT in a Great Pyrenees dog: a 14-base insertion in exon 13 and a splicing defect of intron 13. Veterinary
Pathology 37:581-588, 2000.
4. Boudreaux MK and Catalfamo JL. Molecular and genetic basis for thrombasthenic thrombopathia in
Otterhounds. Am J Vet Res 62(11):1797-1804, 2001.
The sample required for testing for GT in Otterhounds is a 2 ml EDTA tube (purple top)
containing at least 1 ml of whole blood. Care should be taken to not cross contaminate samples
during collection, particularly if more than one dog is collected at the same time. Samples should
be labeled clearly so that there is no confusion regarding sample identification. Samples should
be kept cold (ice packs) and shipped overnight to the address below. Take care to make sure
tubes are protected well to prevent breakage during shipping. Please do not ship on Friday or the
day before a holiday. The fee for testing is $50 per sample. Make checks payable to: Auburn
University, Department of Pathobiology.
Please provide the following information on each dog being tested:
Name and AKC Registration Number
Male or Female (Circle one)
Age at time of sampling or Date of Birth
AKC Registration Number of Sire
AKC Registration Number of Dam
I am hereby requesting this sample be tested for the single base pair change in Exon 12
causing Type I Glanzmanns thrombasthenia in Otterhounds. I understand that my
individual test results will only be released to me. I certify that I am the owner of this dog.
I understand and agree that the results of this test may be confidentially combined with
those of other owners and used in aggregate result form for research purposes including
publication. I understand in aggregate result form my individual results will not be
identifiable specifically to my dog. I release Dr. Boudreaux and any associates working
with her and Auburn University from all liability regarding this sample.
Owners Signature Date
Owners Name (print clearly or type) Telephone number
should be sent to:
Send samples to: Mary K. Boudreaux, DVM, PhD
Department of Pathobiology
166 Greene Hall
College of Veterinary Medicine
Auburn University, Alabama 36849-5519