Glanzmann’s Thrombasthenia

 

Gene: ITGA2B

Transmission: Autosomal recessive

For an autosomal recessive genetic disease an animal must have two copies of the mutation in question to be at risk of developing the disease.  Both parents of an affected animal must be carriers of at least one copy of the mutation.  Animals that have only one copy of the mutation are not at risk of developing the disease but are carrier animals that can pass the mutation on to future generations.

Mutation: Substitution, ITGA2B gene; G>C, exon2

Breeds: Quarter Horse, Thoroughbred crosses, Oldenburg

Age of onset of symptoms:  From 6 months to 3 years

Glanzmann’s thrombasthenia gravis is a genetic coagulation disorder seen in the Quarter Horse, Thoroughbreds, crossbreeds and Oldenburg horses.  Affected animals have a defect in platelet aggregation that presents as chronic epistaxis (nosebleeds), bleeding of gums and/or bleeding beneath the skin (purpura).  This coagulation dysfunction is caused by a defect in the αIIbβ3 subunit of the platelet receptor for fibrinogen, essential for the coagulation reaction.

 

References:

OMIA link: [1000-9796]

Dahlgren AR, Tablin F, Finno CJ. (2021) Genetics of equine bleeding disorders. Equine Vet J 53:30-37.  [pubmed/32463964]

Leite RO, Ferreira JF, Araújo CET, et al. (2019) Prevalence of the Mutations Responsible for Glanzmann Thrombasthenia in Horses in Brazil. Animals (Basel) 9(11):960.  [pubmed/31766112]

Macieira S, Lussier J, Bédard C. (2011) Characterization of the cDNA and genomic DNA sequence encoding for the platelet integrin alpha IIB and beta III in a horse with Glanzmann thrombasthenia. Can J Vet Res. 75(3):222–227. [pubmed/22210999]