Genomewide association study reveals a risk locus for equine metabolic syndrome in the Arabian horse.

The study highlights the discovery of a genetic locus related to equine metabolic syndrome (EMS) in Arabian horses that could potentially be used for early identification and hence, help manage obesity in horses. This was done by conducting a genomewide association study and evaluating certain correlations between identified markers and the disease.

Background of the Study

• The research focuses on equine metabolic syndrome (EMS), a condition prevalent in obese horses and ponies commonly characterized by elevated insulin levels.
• EMS can lead to severe secondary conditions and has clinical similarities with conditions such as pituitary pars intermedia dysfunction, making its diagnosis challenging.
• Given the lack of specific treatments for EMS, the timely identification of potential risk cases can help in the implementation of preventative measures.

Methods and Findings of the Study

• The researchers used a genomewide association study (GWAS) to identify a risk locus for EMS. They examined Arabian horses that had previously suffered from severe laminitis, a condition often associated with EMS.
• They found significant genetic markers close to a particular candidate gene. These markers seemed to play a role in cholesterol regulation within the body.
• The strongest marker, BIEC2-263524, showed a correlation with higher insulin levels and an increased frequency of laminitis. The researchers further confirmed this association in another population of Arabian horses where the marker was related to higher modified insulin-to-glucose ratio (MIRG) values and Body Condition Score (BCS).
• More in-depth examination identified a polymorphic guanine homopolymer and 5 haplotypes in the 3′ untranslated region (UTR). An 11 guanine (11-G) allele at this location also correlated with elevated insulin levels.

Significance and Future Directions

• Screening tests using these identified markers could potentially help diagnose horses that are genetically predisposed to obesity or EMS. This can provide a proactive approach to manage the condition in early stages.
• The identification of the function of FAM174A, the candidate gene identified, could contribute to a better understanding of the origin of EMS and obesity in horses and other species.
• Further investigation of this locus is warranted as it could potentially play a role in obesity and metabolic disorders not just in horses, but in other animal species as well.