Genetic Health Testing for Thoroughbreds

Thoroughbred horses are known for their speed, endurance, and agility, making them the face of the horse racing world. However, like all breeds, they are susceptible to certain genetic health conditions. Understanding these genetic predispositions through DNA testing is crucial for maintaining their health and performance, whether they are racing, eventing, or being used for breeding. Some of the potential genetic health conditions and risks seen in Thoroughbred horses include:

Fragile Foal Syndrome (FFS)

FFS is a genetic disorder that is characterized by extreme skin fragility and hypermobile joints. It was initially named “Warmblood” Fragile Foal Syndrome as it was thought to only affect Warmblood horses but has now been found in additional breeds including the Thoroughbred. Foals with FFS are often born with severe lesions and open wounds due to their fragile skin, and may also suffer from joint laxity, making movement difficult and painful. This condition is caused by a genetic mutation, and foals must inherit two copies of the FFS gene (FFS/FFS) to display symptoms. Horses with only one copy of the gene (FFS/n) are carriers and are not thought to show symptoms but can pass the gene to their offspring. DNA testing for FFS is crucial for breeders to identify carriers and make informed breeding decisions to prevent the birth of affected foals.

West Nile Virus Risk (WNVR)

West Nile Virus (WNV) is a potentially severe viral infection transmitted by mosquitoes, and some Thoroughbreds may have a genetic predisposition for a higher susceptibility to developing severe WNV symptoms. WNV primarily affects the central nervous system, causing symptoms such as fever, ataxia (lack of coordination), and muscle weakness. In severe cases, it can lead to encephalitis, which is an acute inflammation of the brain, or even death. Researchers have identified genetic markers associated with an increased risk of severe WNV symptoms in horses. Horses with one copy of these genetic markers (WNVR/n) may show milder symptoms, which can be managed with supportive care and preventative vaccination. However, horses with two copies of the markers (WNVR/WNVR) may experience more severe symptoms, making it crucial to implement preventive measures, such as vaccination and aggressive mosquito control, to protect these at-risk horses. This is a genetic health risk, meaning if your horse carries one or two copies of the variant, they are not necessarily destined to develop the disease but it does indicate that they are at a higher risk of developing it.

Chronic Idiopathic Anhidrosis Risk (CIAR)

Chronic Idiopathic Anhidrosis is a condition where horses lose the ability to sweat normally, which can be particularly problematic for Thoroughbred horses who may be racing, and those in hot and humid climates. This inability to sweat leads to overheating, decreased performance, and can potentially be life-threatening. Researchers have identified genetic markers associated with an increased risk of developing this condition. Horses with one copy of these markers (CIAR/n) may show milder symptoms, such as partial sweating and reduced heat tolerance, which can be managed with careful monitoring and environmental adjustments. However, horses with two copies of the markers (CIAR/CIAR) are more severely affected and may struggle significantly with temperature regulation. DNA testing for Chronic Idiopathic Anhidrosis is essential for identifying at-risk horses and implementing appropriate management strategies to ensure their overall health and comfort. This test evaluates your horse’s genetic predisposition for having a higher risk of developing severe CIA symptoms but is not a CIA diagnosis or mean that your horse will develop the disease.

Kissing Spines Susceptibility Risk (KSSR)

Kissing spines, also known as overriding dorsal spinous processes, is a painful condition where the bony projections on a horse's vertebrae touch or overlap. This can lead to chronic back pain, reduced performance, and behavioral issues. Some horses are genetically predisposed to this condition, which can affect breeds like the Thoroughbred. Researchers have identified a genetic marker associated with a higher risk of developing more severe kissing spines. Horses with one copy of this marker (KSSR/n) have a moderate risk of developing a higher grade of kissing spines, are more likely to fall into the grade 2 (densification of the margins) diagnosis category if the disease presents itself, and have a 50% chance of passing the variant onto any offspring. Horses with two copies of the variant (KSSR/KSSR) face an increased risk for developing a higher grade of kissing spines, are more likely to fall into the category of grade of 3 (bone lysis adjacent to the margins) to 4 (severe remodeling) should the disease arise, and have a 100% change of passing the variant onto any future foals. This test assesses the genetic predisposition for higher KS severity risk, it is not a diagnosis of the condition or mean your horse will definitely develop it. However, having this knowledge means you can take proactive steps to maintain your Thoroughbred’s health and performance. This is a standalone test that is not included in our standard packages. Order your horse's Kissing Spines Susceptibility Risk test here!

Identifying the genetic health risks and conditions known to affect Thoroughbred horses is key to managing their health and performance, whether you plan to breed them or not. Our comprehensive Health Panel DNA test provides you with the insights to know your Thoroughbred down to their DNA, revealing these potential health conditions and many more. By learning about your Thoroughbred’s genetic health conditions and/or risks early, you get a leg up in implementing preventive care and making informed breeding decisions to ensure they have the best shot at a happy and healthy life.