By Mark Andrews

Fragile Foal Syndrome (FFS) is a lethal genetic disease of connective tissue which has been reported most frequently in Warmbloods. However, a recent study has found that the genetic defect responsible is present across a range of other breeds.

Affected foals are typically aborted during late gestation or born as non-viable foals. If alive at birth, they tend to have problems such as fragile skin, skin defects, hyperextension of the joints, and difficulty breathing, and generally require euthanasia within days.

FFS has been shown to be an autosomal recessive genetic condition. Carrier animals with one copy of the defective gene (PLOD 1 c.2032 G>A) will be normal, but if mated with another carrier may produce an affected foal.

It is now known that the condition is not confined to Warmblood horses.

Research by Katie Martin and colleagues at Etalon Diagnostics in Menlo Park, California (a company that offers genetic testing), together with Dr. Samantha Brooks at the University of Florida in Gainesville, and Dr. Scott McClure of Midwest Equine in Iowa, found that the genetic defect occurs across other horse populations.

The team examined samples from 7343 horses from various breeds or type of horse. The defective gene occurred in 5.32 percent of Warmblood type horses. In other affected breeds it was less than one percent. They found no sign of the defect in Arabians, Iberians, Ponies, or Thoroughbreds. The study observed FFS carriers among diverse populations with no identifiable common ancestor.

Studies of the frequency of the defect in aborted or stillborn foals are lacking, making the potential economic effect of FFS on the horse breeding industry unknown.

The researchers suggest that pre-breeding testing should be used to inform the breeding program, allowing breeders to avoid breeding two carriers together, thus reducing the frequency of the FFS gene in the population as well as the number of lost pregnancies.

Related: Warmblood Fragile Foal Syndrome Type 1

Photo: Dreamstime/Annalie Coetzer