WFFS, or "Warmblood Foal Fragility Syndrom"


WFFS is a genetic disease that is well known to breeders and stallions. It is mainly seen in sport horses and is only transmitted through breeding animals. Screening can help to avoid cross-breeding which could lead to the foal being affected.

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WFFS causes the foal to have extremely fragile skin due to poor collagen in the epidermis. Sores and skin lesions will appear on the foal, especially at pressure points. Foals with WFFS also have difficulty standing due to hyperlaxity of the joints. There is no known treatment and the life span of the affected foal will usually not exceed 8 days.

For a foal to be born with WFFS, both parents must be carriers. Horses carrying only one copy of the gene are perfectly healthy.


Three different genotypic combinations are possible. Individuals are thus considered:

- Non-carriers ⇒ They cannot transmit the defect. Their genotype is n/n.

- Healthy carriers ⇒ They are not sick, but can transmit the anomaly. Their genotype is n/WFFS.

- Carriers ⇒ They express the disease rapidly after birth and are usually euthanised. Their genotype is WFFS/WFFS. 


Fortunately, a blood test by a veterinarian or a hair bulb sample will allow the breeder to know the genotypic combination of his horse for a fee of between 40 and 60€.

For more information on Fragile Foal Syndrome, read this article and webconference (in french) produced by the IFCE (Institut Français du Cheval et de l'Équitation).