Genomic Association Of A Potassium Channel To Chronic Idiopathic Anhidrosis In Stock-Type Horses

Equine Anhidrosis is characterized by persistent reduction or complete lack of a sweat response to appropriate stimuli. The common signs, including poor performance, overheating and rapid breathing, can progress to hyperthermic shock and sudden death. About 40% of show horses experience anhidrosis and prevalence is estimated at 11% at farm or equine facility and 2% at the animal level in the state of Florida. Risk varies significantly by breed and the odds of developing anhidrosis are 21.67 times higher in horses with a family history of the condition, highlighting a genetic component to this disease. We gathered information for 390 horses through a 96-question online survey. Filtering for confounding medications or conditions that can mimic CIA left 178 horses (100 cases, 78 controls) for genotyping on the Affymetrix 670k genotyping array. A GWAs was performed on a genetically matched 1:1 case/control set, totaling 200 individuals. We investigated polymorphisms correlated to CIA within GWAs-identified candidate regions, on 10x Chromium (10x Genomics Inc.) re-sequenced genomes of a CIA affected individual and a control. We also evaluated polymorphism effects with PolyPhen2, Human Splicing Finder and I-TASSER. We anticipate that this work will be followed by development of genetic diagnostic tools for causative mutations leading to CIA, as well as innovative treatments for this condition in diverse equine breeds.