Fragile foal syndrome

Carrier

Your horse has ONE fragile foal syndrome gene mutation.

This means that your horse does not have the disease but is a carrier of the mutation.

Horses with just one gene mutation are clinically unaffected and can live normal lives without any limitations on performance.

Breeding implications

If you breed your horse with a mate that does not have the fragile foal syndrome mutation, there is:

  • A 50% chance the foal will not have this mutation.
  • A 50% chance the foal will have one gene mutation and be disease free, like your horse

If you choose to breed your horse with another horse that also has one mutation, there is:

  • A 25% chance the foal will not have this mutation.
  • A 50% chance the foal will have one gene mutation and be disease free, like your horse.
  • A 25% chance the foal will have the disease.

If you breed your horse with a mate that is affected with this disease, there is:

  • A 50% chance the foal will have one gene mutation and be disease free, like your horse.
  • A 50% chance the foal will have the disease.
What is fragile foal syndrome?

Fragile foal syndrome is a genetic disease that causes skin lesions, hyperextensible limb joints and fetlock anomalies, which prevent affected foals from standing normally.

The forelimbs, neck and abdomen are the area’s most afflicted, and if the foal survives birth, they will develop serious secondary infections over the following days and suffer from escalating pain. Since the disease is incurable, affected foals are usually humanely euthanized shortly after birth.

What are the symptoms?
  • Hyperextensible, loose limb joint.
  • Deformed fetlocks.
  • Accumulation of fluid.
  • In some cases, foals are born with an open abdomen and wound in the abdomen, through which the small intestines protrude.
  • Subcutaneous emphysema (air trapped under the skin).
  • Hematomas.
  • Premature or stillbirth.
How is it inherited?

Fragile Foal Syndrome is a recessive condition, which means your horse must have two copies of the mutation to be affected. However, as your horse has only one copy of the mutation, it is called a carrier, without having the disease.

Genomic Details

Cerebellar abiotrophy is caused by a disease gene variant of the TOE1 gene that is on chromosome 18. This gene is thought to be involved in the development of Purkinje neurons, which help to coordinate movement in the part of the brain called the cerebellum. When these Purkinje neurons do not form, the horse has coordination and movement problems.

The mutation that causes fragile foal syndrome is a switch in one of the four base pairs that make up a DNA molecule. Cytosine (C) is replaced by Thymine (T) changing the PLOD1 gene. Therefore, a horse’s genetic result for fragile foal syndrome is one of three possibilities:

 

  1. G/G: Normal. Does not have the disease. Does not have the mutation.
  2. G/A: Carrier. Does not have the disease. Carries one gene mutation from one parent. This might be passed to their foal.
  3. A/A: Affected. Has the genetic disease. The horse has inherited a gene mutation from each parent. One mutation will be passed to their foal.