→ Connective tissue disorder leading to the death of the foal.
- Majority of foals are not carried to term – most are spontaneously aborted or stillborn
- Newborn foals have skin detachment from the body without external influence
- Separation of skin and subcutis without bleeding.
- Foal makes no or only weak attempts to get up.
- Hypermobile joints.
- Connective tissue disease in warmbloods and related breeds that leads to skin detachment.
- Mutation in the PLOD1 gene. This encodes the PLOD1 protein, which supports the collagen fibres so that they can fold and connect → Essential for the structural integrity of the body: skin, membrane, joints.
- Affected animals must always be humanely euthanized with hours.
- Similar to human connective tissue disease “Ehlers-Danlos syndrome” (type IV), also caused by a mutation in the PLOD1 gene (LH1)
- Hypothesis: Most (W)FFS pregnancies end in spontaneous abortions.
- Starting in January 2019, all stallions active in breeding in Germany must be tested and the results have to be made public (registration regulations stallion book I / II according to ZVO).
Inheritance: autosomal recessive
→ Only animals with two copies of the variant (ffs/ffs) are affected. Animals with only one copy (N/ffs) are clinically normal carriers.
|Genotype:||The horse is:
|N/N||normal.||The horse has no copies of the mutations causative for (Warmblood) Fragile Foal Syndrome and therefore cannot pass it on to its offspring.|
|N/ffs||a carrier.||The horse is a clinically normal carrier. The variant will be passed on to its offspring with a probability of 50%.|
|ffs/ffs||affected.||The horse does not survive more than a few hours.|
- Carriers may be bred to normal animals (N/ffs x N/N) without any risk of producing affected offspring. The offspring should also be tested before breeding to determine if they are carriers or normal.
- Breeding two carriers (N/ffs x N/ffs) is not recommended due to the possibility of 25% of the offspring being affected.
- Affected animals (ffs/ffs) usually die within a few hours.
Test information: This test detects a mutation in the PLOD1 gene. This test is performed by partner laboratory.
Monthoux, C., de Brot, S., Jackson, M., Bleul, U., Walter, J.: Skin malformations in a neonatal foal tested homozygous positive for Warmblood Fragile Foal Syndrome. BMC Vet Res 11:12, 2015. Pubmed reference: 25637337. DOI: 10.1186/s12917-015-0318-8.
On 12.04.2019, CAG Scientific Lead Melissa Cox gave a presentation about Warmblood Fragile Foal Syndrome at the 6. Liebenberger Pferdeforum. The presentation (in German) is now available for anyone who is interested in learning more about the disease. 2019-04-12 CAG GmbH – Liebenberger Pferdeforum – WFFS – Cox
Further information is available at Online Mendelian Inheritance in Animals.