Prevalence of the Mutations Responsible for Glanzmann Thrombasthenia in Horses in Brazil.
Authors: Leite Raíssa O, Ferreira Júlia F, Araújo César E T, Delfiol Diego J Z, Takahira Regina K, Borges Alexandre S, Oliveira-Filho Jose P
Journal: Animals : an open access journal from MDPI
Summary
Glanzmann thrombasthenia, an autosomal recessive bleeding disorder affecting platelet function and causing spontaneous haemorrhage and epistaxis, results from one of two known mutations in the equine ITGA2B gene (a point mutation c.122G>C or a 10-base-pair deletion g.1456_1466del); whilst documented in Quarter Horses, Thoroughbreds, Oldenburgs and Peruvian Pasos across North America, Japan and Australasia, no prevalence data existed for affected populations. Brazilian researchers screened 1,053 DNA samples from clinically healthy Quarter Horses (n=679) and Warmbloods (n=374) using PCR amplification and sequencing of the ITGA2B locus, finding zero carriers and 100% wild-type genotypes across both breeds. Although these findings suggest the condition is either absent or extremely uncommon in the studied Brazilian horse population, the authors acknowledge that their sample, whilst substantial, cannot completely exclude the presence of rare mutant alleles in horses not included in the screening. For equine practitioners, the results offer reassurance regarding genetic disease risk in Brazilian-sourced Quarter Horses and Warmbloods, though genetic testing of breeding stock from other regions remains prudent, particularly in bloodlines with documented familial bleeding disorders or unexplained epistaxis.
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Practical Takeaways
- •GT is not a practical concern in screening Quarter Horses and Warmbloods in Brazil based on current prevalence data
- •Veterinarians encountering unexplained hemorrhage or epistaxis in these breeds should consider differential diagnoses, as GT is effectively absent in the Brazilian populations studied
- •Breeders importing horses from regions with documented GT prevalence (USA, Canada, Japan, Australia) should consider genetic screening
Key Findings
- •No carriers of ITGA2B mutations (c.122G>C or g.1456_1466del) were identified in 1053 Brazilian horses (679 Quarter Horses and 374 Warmbloods)
- •All tested animals were wild type for both known GT-associated mutations
- •GT appears extremely rare in the Brazilian Quarter Horse and Warmblood populations, though presence of mutated alleles cannot be completely ruled out