A genome-wide association study identifies risk loci to equine recurrent uveitis in German warmblood horses.
Authors: Kulbrock Maike, Lehner Stefanie, Metzger Julia, Ohnesorge Bernhard, Distl Ottmar
Journal: PloS one
Summary
# Editorial Summary: Genetic Risk Factors in Equine Recurrent Uveitis Equine recurrent uveitis (ERU) affects between 3–15% of the horse population, yet its underlying genetic predisposition remains poorly understood. Kulbrock and colleagues conducted a genome-wide association study (GWAS) using SNP genotyping on 144 German warmblood horses to identify chromosomal regions conferring susceptibility to the disease. Two significant loci emerged from their analysis: a SNP on equine chromosome 20 (position 49.3 Mb) near the IL-17A and IL-17F genes, which accounted for 23% of phenotypic variance in ERU development, and a separate SNP on chromosome 18 adjacent to the crystalline gene cluster (CRYGA-CRYGF) that correlated with disease severity and cataract formation. These findings suggest that interleukin-17 signalling plays a critical immunological role in ERU pathogenesis, whilst genetic variation affecting lens crystallins may predispose to secondary cataract complications—a frequent cause of blindness in ERU cases. For practitioners, these genetic markers could support breeding decisions and prognostic discussions with owners, though further validation in other populations will be necessary before implementing SNP testing into routine management protocols.
Read the full abstract on PubMed
Practical Takeaways
- •ERU has a measurable genetic component in German warmbloods; genetic testing and selective breeding could potentially reduce disease incidence in this population
- •Immune pathway involvement (IL-17A/F) suggests potential therapeutic targets beyond traditional anti-inflammatory management
- •Horses carrying risk haplotypes may warrant closer ophthalmologic monitoring for secondary cataract development
Key Findings
- •A significant SNP on equine chromosome 20 at 49.3 Mb near IL-17A and IL-17F genes explains 23% of phenotypic variance for ERU susceptibility
- •A second SNP on chromosome 18 near the crystalline gene cluster (CRYGA-CRYGF) is associated with ERU severity and potential cataract formation
- •Haplotype analysis confirmed significant associations at both genomic regions for ERU risk