OMIA 001000-9796 : Thrombasthenia in Equus caballus
Category: Haematopoietic system phene
Links to MONDO diseases: No links.
Mendelian trait/disorder: yes
Mode of inheritance: Autosomal recessive
Considered a defect: yes
Key variant known: yes
Year key variant first reported: 2006
Cross-species summary: More specifically called Glanzmann thrombasthenia.
Molecular basis: Christopherson et al. (2006) reported a "single guanine to cytosine (CGG to CCG) substitution in codon 41 in exon 2" of ITGA2B that "would result in the substitution of a proline for an arginine in a highly conserved region of the encoded protein" as a likely causal variant in an affected Thoroughbred cross and in an affected Quarter Horse. Noting that the affected Quarter Horse was only heterozygous for this variant, Christopherson et al. (2006) hypothesised that this horse " is likely a compound heterozygote" for this variant and a second yet-to-be-discovered variant.
Christopherson et al. (2007) reported that the second variant in the affected Quarter Horse described in 2006 is "a 10-bp deletion including the splice site between exon 11 and intron 11 . . . [that] would be predicted to result in a lack of splicing of intron 11 and inclusion of a premature stop codon 50 bp downstream of the mutation in the incompletely spliced mRNA."
Sanz et al. (2011) reported the same 10-bp deletion as being likely causative in a Peruvian Paso mare.
Macieira et al. (2011) reported "A point mutation from G to C in exon 2 of ITGA2B causing a substitution of the expected amino acid arginine 72 (Arg(72)) by a proline (Pro(72))" as the likely causal variant for an affected Oldenburg filly, stating that this variant "corresponds" to the variant reported by Christopherson et al. (2006).
Prevalence: Leite et al. (2020) reported that the two known likely causal variants were completely absent from 1053 DNA samples of clinically healthy Quarter Horse (n = 679) and Warmblood horses (n = 374) in Brazil, consistent with the observation that "this disease has not been described in Brazil". Although their samples were of adequate size, the authors rightly concluded that "it is not possible to affirm that there are no horses carrying mutated alleles in Brazil."
|Symbol||Description||Species||Chr||Location||OMIA gene details page||Other Links|
|ITGA2B||integrin alpha 2b||Equus caballus||11||NC_009154.3 (19241506..19257092)||ITGA2B||Homologene, Ensembl, NCBI gene|
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WARNING! Inclusion of a variant in this table does not automatically mean that it should be used for DNA testing. Anyone contemplating the use of any of these variants for DNA testing should examine critically the relevant evidence (especially in breeds other than the breed in which the variant was first described). If it is decided to proceed, the location and orientation of the variant sequence should be checked very carefully.
Since October 2021, OMIA includes a semiautomated lift-over pipeline to facilitate updates of genomic positions to a recent reference genome position. These changes to genomic positions are not always reflected in the ‘acknowledgements’ or ‘verbal description’ fields in this table.
|OMIA Variant ID||Breed(s)||Variant Phenotype||Gene||Allele||Type of Variant||Source of Genetic Variant||Reference Sequence||Chr.||g. or m.||c. or n.||p.||Verbal Description||EVA ID||Inferred EVA rsID||Year Published||PubMed ID(s)||Acknowledgements|
|164||Quarter Horse (Horse) Thoroughbred (Horse)||Thrombasthenia||ITGA2B||missense||Naturally occurring variant||EquCab3.0||11||g.19245752G>C||c.215G>C||p.(R72P)||NM_001081793.1; NP_001075262.1; originally published as p.(R41P) and listed by Leite et al. (2019) as c.122G>C; coordinates in this table have been updated to a recent reference genome and / or transcript||2006||16407493|
|512||Peruvian Paso (Horse) Quarter Horse (Horse)||Thrombasthenia||ITGA2B||deletion, small (<=20)||Naturally occurring variant||EquCab3.0||11||g.19247983_19247992del||g.19247983_19247992delCAGGTGAGGA||2007||17338169||g. coordinates obtained from Dahlgren et al. (2020)|
Note: the references are listed in reverse chronological order (from the most recent year to the earliest year), and alphabetically by first author within a year.
|2021||Dahlgren, A.R., Tablin, F., Finno, C.J. :|
|Genetics of equine bleeding disorders. Equine Vet J 53:30-37, 2021. Pubmed reference: 32463964. DOI: 10.1111/evj.13290.|
|2019||Leite, R.O., Ferreira, J.F., Araújo, C.E.T., Delfiol, D.J.Z., Takahira, R.K., Borges, A.S., Oliveira-Filho, J.P. :|
|Prevalence of the Mutations Responsible for Glanzmann Thrombasthenia in Horses in Brazil. Animals (Basel) 9:, 2019. Pubmed reference: 31766112. DOI: 10.3390/ani9110960.|
|2011||Macieira, S., Lussier, J., Bédard, C. :|
|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 75:222-7, 2011. Pubmed reference: 22210999.|
|Sanz, MG., Wills, TB., Christopherson, P., Hines, MT. :|
|Glanzmann thrombasthenia in a 17-year-old Peruvian Paso mare. Vet Clin Pathol 40:48-51, 2011. Pubmed reference: 21291483. DOI: 10.1111/j.1939-165X.2011.00289.x.|
|2007||Christopherson, PW., van Santen, VL., Livesey, L., Boudreaux, MK. :|
|A 10-base-pair deletion in the gene encoding platelet glycoprotein IIb associated with Glanzmann thrombasthenia in a horse. J Vet Intern Med 21:196-8, 2007. Pubmed reference: 17338169.|
|Macieira, S., Rivard, G.E., Champagne, J., Lavoie, J.P., Bédard, C. :|
|Glanzmann thrombasthenia in an Oldenbourg filly. Vet Clin Pathol 36:204-8, 2007. Pubmed reference: 17523098.|
|2006||Christopherson, PW., Insalaco, TA., van Santen, VL., Livesey, L., Bourne, C., Boudreaux, MK. :|
|Characterization of the cDNA Encoding alphaIIb and beta3 in normal horses and two horses with Glanzmann thrombasthenia. Vet Pathol 43:78-82, 2006. Pubmed reference: 16407493. DOI: 10.1354/vp.43-1-78.|
|2005||Livesey, L., Christopherson, P., Hammond, A., Perkins, J., Toivio-Kinnucan, M., Insalaco, T., Boudreaux, MK. :|
|Platelet dysfunction (Glanzmann's thrombasthenia) in horses. J Vet Intern Med 19:917-9, 2005. Pubmed reference: 16355691.|
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