Foal immunodeficiency syndrome / FIS (SLC5A3-related) - Fell and Dales pony

Foal Immunodeficiency Syndrome in Fell and Dales ponies

This genetic test detects the SLC5A3 variant c.1337G>T that causes Foal Immunodeficiency Syndrome, abbreviated FIS, in Fell and Dales ponies. The disorder is a severe inherited immunodeficiency of foals.

Affected foals often appear normal at birth but usually develop progressive anemia and recurrent infections during the first weeks of life. Typical signs include weakness, poor growth, diarrhea, coughing, respiratory problems, failure to suckle properly and reduced immune protection.

Practical value of this test

• GG: the animal does not carry the tested FIS variant.
• GT: the animal is a carrier and can pass the variant on.
• TT: this genotype causes FIS; affected foals usually die young or require euthanasia.

FIS is inherited as an autosomal recessive disorder. This test is highly valuable for breeding decisions: identifying carriers makes it possible to avoid carrier-to-carrier matings while still using valuable carriers responsibly when paired with clear animals.