Prevalence of the RAPGEF5 c.2624C>A and PLOD1 c.2032G>A variants associated with equine familial isolated hypoparathyroidism and fragile foal syndrome in the US Thoroughbred population (1988-2019).
- Journal Article
Summary
The research article studies the prevalence of certain genetic variants related to fatal conditions, termed Equine familial isolated hypoparathyroidism (EFIH) and fragile foal syndrome (FFS), in Thoroughbred foals. The article aims to understand the variants’ frequency over time and if they are influenced by breeding practices.
Identification of genetic issues in thoroughbred foals
In this study, the researchers focused on exploring the variants associated with two fatal recessive Thoroughbred foals’ conditions—Equine familial isolated hypoparathyroidism (EFIH) and Fragile foal syndrome (FFS). The genetic causes of these conditions were:
- RAPGEF5 c.2624C>A causing EFIH
- PLOD1 c.2032G>A leading to FFS
The researchers’ aim was to understand the frequency of these genetic variants in the US Thoroughbred population from 1988 to 2019.
Methodology
This research was a population allele frequency study using genomic DNA from hair and serum samples. The samples were genotyped for the EFIH and FFS. The researchers compared the allele frequencies between two cohorts, classified by year of birth (1988-2000, n = 728) and (2001-2019, n = 1059), and across the seven geographical regions of the United States. The frequency comparison was performed using Fisher’s Exact tests.
Findings
It was found that both EFIH and FFS allele frequencies did not vary significantly between the two time points observed. No EFIH or FFS homozygotes were detected. However, a sample from 1992 was identified as a carrier for EFIH, and one from 1993 was recognized as an FFS carrier. Geographical changes in the distribution of carriers, for both conditions, were insignificant.
Conclusion
The analysis concluded that EFIH and FFS variants are present but at a low frequency in the United States Thoroughbred population, meaning that these are not recent mutations. The study found no evidence of changes in allele frequency over time. However, due to the closed studbook and breeding practices, it is recommended to continue monitoring breed allele frequencies and genetic testing. This will help circumvent the mating of carriers and the production of affected foals.
Cite This Article
Publication
Researcher Affiliations
- Department of Population Health and Reproduction, School of Veterinary Medicine, University of California-Davis, Davis, California, USA.
- Veterinary Genetics Laboratory, School of Veterinary Medicine, University of California-Davis, Davis, California, USA.
- Department of Population Health and Reproduction, School of Veterinary Medicine, University of California-Davis, Davis, California, USA.
- Veterinary Genetics Laboratory, School of Veterinary Medicine, University of California-Davis, Davis, California, USA.
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California-Davis, Davis, California, USA.
- Department of Population Health and Reproduction, School of Veterinary Medicine, University of California-Davis, Davis, California, USA.
MeSH Terms
- Animals
- Horses / genetics
- Prevalence
- Genotype
- Alleles
- Reproduction
- Syndrome
- Hypoparathyroidism / genetics
- Hypoparathyroidism / veterinary
- Horse Diseases / epidemiology
- Horse Diseases / genetics
Grant Funding
- L40 TR001136 / NCATS NIH HHS
- 5T35OD010956-22 / NIH Office of the Director
- UC Davis Veterinary Genetics Laboratory
- UC Davis Center for Equine Health
Conflict of Interest Statement
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