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Glanzmann Thrombasthenia (ITGA2B gene, Pyrenean Mountain Dog)

Glanzmann Thrombasthenia (ITGA2B gene, Pyrenean Mountain Dog)

Glanzmann's thrombasthenia is a rare autosomal recessive disorder that affects platelet function and causes bleeding. It is due to a defect in the platelet glycoprotein IIb/IIIa receptor that causes platelets to fail to aggregate.

Symptoms

Dogs with Glanzmann's thrombasthenia may present with clotting problems and bleeding spontaneously or after minor trauma, surgery or dental procedures. Clinical signs may include excessive bleeding, bruising, nosebleeds, bleeding gums and anemia.

Disease Management

Treatment for Glanzmann's thrombasthenia in dogs focuses on relieving symptoms and preventing bleeding episodes. In severe cases or during surgery, transfusions of blood or platelet concentrates may be necessary. In addition, it is crucial to avoid medications that can affect platelet function. If you have a dog with this disease, it is essential to consult your veterinarian on how to manage the symptoms and ensure proper care.

Genetic basis

This disease follows an autosomal recessive mode of inheritance. Autosomal recessive inheritance means that the dog, regardless of sex, must receive two copies of the mutation or pathogenic variant to be at risk of developing the disease. Both parents of an affected dog must carry at least one copy of the mutation. Animals with only one copy of the mutation are not at increased risk of developing the disease, but may pass the mutation on to future generations. Breeding between dogs carrying genetic variants that can cause disease, even if they do not show symptoms, is not recommended.

Technical report

In dogs with Glanzmann's thrombasthenia, platelet aggregation in response to ADP, thrombin and collagen is absent, even though platelet count, platelet morphology and VWF concentration are normal. This disease has been best characterized in the Great Pyrenean dog. It has also been observed in Otterhounds, and more recently in two closely related mongrel dogs and a Golden Retriever. Lipscomb et al. observed that Glanzmann's thrombasthenia in the Great Pyrenees dog was due to a mutation in the ITGA2B gene encoding the alpha subunit of the platelet fibrinogen receptor called integrin αIIbβ3. This integrin is crucial for platelet aggregation and blood clot formation. The c.1360_1373dup mutation in the ITGA2B gene produces a 14 bp insertion that results in a truncated protein.

Most affected breeds

Golden Retriever
Great Pyrenees
Mixed breed
Otterhound

Bibliography

Boudreaux MK, Kvam K, Dillon AR,et al. Type I Glanzmann's thrombasthenia in a Great Pyrenees dog. Vet Pathol. 1996 Sep;33(5):503-11.

Cortese L, Christopherson PW, Pelagalli A. Platelet Function and Therapeutic Applications in Dogs: Current Status and Future Prospects. Animals (Basel). 2020 Jan 25;10(2):201.

Lipscomb DL, Bourne C, Boudreaux MK. Two genetic defects in alphaIIb are associated with type I Glanzmann's thrombasthenia in a Great Pyrenees dog: a 14-base insertion in exon 13 and a splicing defect of intron 13. Vet Pathol. 2000 Nov;37(6):581-8.