Equine Metabolic Syndrome / Laminitis Risk (EMS / LAM)
Gene or Region: FAM174A
Reference Variant: T
Mutant Variant: C
Affected Breeds: Many
Research Confidence: Preliminary - Strong correlation in early studies, results have shown strong correlation in early studies of Arabian population
Explanation of Results: EMS/EMS = homozygous for Equine Metabolic Syndrome, at risk for EMS and increased risk for EMS-related Laminitis EMS/n= heterozygous for Equine Metabolic Syndrome, at risk for EMS and increased risk for EMS-related Laminitis n/n = no variant detected
General Description for Equine Metabolic Syndrome
Equine Metabolic Syndrome (EMS) is a wide-spread issue in the horse population. Primarily characterized by hyperinsulinemia (excess insulin circulating in the blood in relation to glucose levels), this metabolic disorder is often present in obese horses and ponies and can be challenging to diagnose as it can be misdiagnosed as "Cushing's" (a pituitary disfunction). Few treatments exist for EMS outside of diet management and exercise, which increases the need for early detection and prevention. Should obesity be allowed to set in, secondary chronic conditions, such as Laminitis can easily follow and further compromise the health of the horse. Breeders have also observed that horses with a tendency toward obesity (EMS) can also be difficult to manage in a reproductive environment (difficult to get in foal).
A genomewide association study (GWAS) using Arabian horses with a history of severe Laminitis secondary to EMS revealed significant genetic markers near a single candidate gene that may play a role in cholesterol homeostasis. This same genetic candidate correlated with a 9 time greater risk for Laminitis in horses with one or more variants that were also overweight/obese.
EMS Risk
-/- = n/n - No EMS variants detected. Normal risk for EMS and Laminitis +/- = EMS/n - One EMS variant detected. Horse is at risk for EMS and at increased risk for Laminitis +/+ = EMS/EMS - Two EMS variants detected. Horse is at risk for EMS and at increased risk for Laminitis (9 times greater risk than "normal" horses with no EMS variant)
EMS-Related Laminitis Risk
-/- = n/n - No EMS-LAM variants detected. Normal risk for EMS-related Laminitis +/- = EMS/n - One EMS-LAM variant detected. Horse is at increased risk for EMS-related Laminitis* +/+ = EMS/EMS - Two EMS-LAM variants detected. Horse is at increased risk for EMS - related Laminitis*
*9 times greater risk than "normal" horses with no EMS variant
References
Lewis, S. L., Holl, H.M, Streeter, C., Posbergh, C., Schanbacher, B. J., Place, N. J., Mallicote, M. F., Long, M. T., Brooks, S. A. (2017) Genomewide association study reveals a risk locus for equine metabolic syndrome in the Arabian horse. J Anim Sci 2017 Mar;95(2) 1071-1079
More Horse Health
Occipitoatlantoaxial Malformation 1
Occipitoatlantoaxial Malformation 1 (OAAM1) is an inherited developmental condition predominantly found in Arabian horses, characterized by abnormal development of the cervical vertebrae leading to compression of the upper cervical cord and subsequent neurological damage.
Polysaccharide Storage Myopathy
Polysaccharide Storage Myopathy (PSSM) is a glycogen storage disorder in which affected horses have chronic episodes of exertional rhabdomyolysis (“tying-up”). Acute symptoms are an unwillingness to move and muscle damage following exercise. Moderate symptoms can usually be managed through a low-sugar/starch diet and exercise.
Recurrent Laryngeal Neuropathy
Recurrent Laryngeal Neuropathy (RLN) is a disease that results in loss of the neurons that open the larynx, significantly affecting performance in Thoroughbreds and other sport horses. It is an important issue for horses in competitive events because the resultant paralysis of the larynx leads to obstruction of air flow during intense exercise, creating the abnormal inspiratory noise that gives RLN its common name: “roaring”.