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Warmblood Fragile Foal Syndrome (WFFS)

Questions & Answers: WFFS FAQ

Warmblood Fragile Foal Syndrome (WFFS) is a topic of importance among breeders. Information about this genetic defect is scattered among many sources. Below are some answers to the most frequently-asked questions. 

1. What is Warmblood Fragile Foal Syndrome (WFFS or FFS)?
2. What is the science behind Warmblood Fragile Foal Syndrome?
3. Scientifically, when was WFFS first discovered? Technical stuff here….
4. How long have we known about it?
5. What other genetic conditions are horses tested for?
6. What action did registries take once WFFS was reported?
7. Does Canadian Warmblood have a plan and testing in place?
8. What are the European regulations doing about reporting and testing for WFFS?
9. How does a horse get WFFS?
10. What is the difference between 'having' WFFS and being a carrier?
11. Is WFFS really a disease?
12. Is WFFS limited to warmbloods?
13. Is WFFS the same as HERDA?
14. Can my horse get WFFS from another horse who is a carrier?
15. Do carriers get sick?
16. How do I know if my horse is a carrier (N/WFFS)?
17. Should I test my riding horses?
18. How long has WFFS been around?
19. Do we know who the first horse was who had the gene mutation?
20. What does WFFS mean for breeders?
21. How many horses are carriers for WFFS?
22. Can we stamp out WFFS?
23. Why are all known carriers not immediately taken from breeding?
24. If we don't stamp out WFFS, how do we live with it?
25. Should carriers be 'culled'?
26. Should I stop breeding my carrier mare?
27. How do I find out if my mare is a carrier (N/WFFS)?
28. I have a carrier mare. Is it safe to breed her?
29. I want to breed my carrier mare but only to a clear stallion. How do I find out if a stallion is a carrier?
30. Is it possible to know if a stallion is a carrier if he's deceased?
31. I have a carrier stallion. Is it safe to use him?
32. Are there legal implications to be aware of with WFFS?
33. My mare is clear (N/N) for WFFS. How can her foal be a carrier (N/WFFS)?
34. If my horse is clear, does that mean the parents are clear too?
35. Why are so few foals born with WFFS?
36. Is mandatory testing and reporting something breeders want to see?
37. Conclusions

WFFS inheritance

1. What is Warmblood Fragile Foal Syndrome (WFFS or FFS)?
Warmblood Fragile Foal Syndrome (WFFS) is a fatal disorder caused by an inherited genetic defect. The defective gene is one that is critical in the production of collagen. 
Affected foals have 'hyperextensible, abnormally thin, fragile skin and mucous membranes (tissue that lines cavities and covers organs) that cause extensive lesions throughout the body.' Signs of the disease are present from birth. Foals that survive birth, will have to be euthanized.
WFFS is a recessive trait, which in this case means that horses can be:
• N/N (clear) - they have two copies of the dominant allele (version of the gene). They do not have or carry the defective WFFS gene and cannot pass it on to their offspring. They are clear of the mutation.
• N/WFFS (carrier) - they have one copy of the allele with the WFFS mutation and one without. They are perfectly normal, but are able to pass the mutation on to their offspring some of the time (50%). Horses who are N/WFFS are carriers of the mutation but do not have the defect.
• WFFS/WFFS (positive) - they have the defect and might be aborted before birth. If they are born alive, they are as described above and must be euthanized. There are no adult horses with WFFS/WFFS status, because they do not survive. No study has yet determined the actual early embryonic or abortion rate.
IMPORTANT: Because the defective WFFS gene is recessive, in order to get a lethal foal, two carrier parents would need to be bred, with a 25% occurrence of the lethal WFFS/WFFS. If you breed a carrier to a horse that is clear of the gene, you will never get a foal with the defect, though you might get a carrier foal with 50% of the pairings. 

2. What is the science behind Warmblood Fragile Foal Syndrome?
WFFS is an inherited autosomal disorder caused by a recessive allele (gene), meaning a foal can only be affected if the foal inherits the disease from both parents as shown in the diagram below. It is easy to understand how WFFS has flown under the radar for the past decade since the test was available. When one considers a variable inheritance of between 9-19%, combined with the hypothesized early fetal loss, further combined with the fact that many if not most breeders and/or Veterinarians could go their entire life and never see or recognize a case.
WFFS remained largely a scientific discovery of little prominence since live births genetically confirmed to WFFS were rare and usually unreported. That was until the 2018 birth of the foal described in the introduction. An internationally prominent sire and two world leader stallion stations (Hilltop Farm, USA & Nijhof, NLD) brought the anomaly to the forefront and a resurgence of testing and research. [1]
Currently, Warmblood registries worldwide, and research facilities including Western College of Veterinary Medicine, SK and Guelph Veterinary College, ON, are conducting studies and offering testing.

3. Scientifically, when was WFFS first discovered? Technical stuff here….
In 2010 (Rüfenacht S et al) [2] described as a case report, a Swiss warmblood horse with symptoms of hereditary equine regional dermal asthenia without mutation in the cyclophylin B gene (PPIB). This was one of several similar cases described in earlier literature, not identified at the time as WFFS, that probably were WFFS based on the genetic testing done at the time.
This causative gene mutation for WFFS was first named in literature in 2011, after which noted genetic researcher, Dr Nena Winand of Cornell University, developed and patented a test for WFFS1 in 2013. [3] WFFS was described as a single mutation in lysyl hydroxylase 1 (LHl) gene. Mutations in LHl are known to cause a similar disorder in humans known as Ehlers-Danlos Syndrome VI (EDSVI).
Monthoux 2015 [4] published the first report describing the clinical and histopathological findings in a foal confirmed to be homozygous (2 copies) positive for WFFS. (Aurich, et al 2019) published 'Characterization of abortion, stillbirth and non-viable foals homozygous for the Warmblood Fragile Foal Syndrome' [5]

4. How long have we known about it?
The mutation was identified in 2011 and the specific gene where the mutation occurs was identified. There were cases described earlier, not identified at the time as WFFS, that probably were WFFS. There has been a DNA test for it since 2013.
There has been some awareness of WFFS in Europe since it was identified, but how much is not known. It did not achieve the status of common knowledge, or the level of open discussion we have now.
In 2018 a foal by Everdale, belonging to a US breeder, was born with WFFS and had to be euthanized. The breeding had been handled by Hilltop Farm, and they and the breeder promptly announced to the world that this had happened. Hilltop Farm went further and tested all their stallions, one of which - Sternlicht - was found to be a carrier, and Hilltop removed him from breeding, at least for 2018. That precipitated the current level of awareness of WFFS. At the same time, the owners of the stallion Everdale, began testing and the KWPN became involved by testing all their active stallions and publishing the results.
Once more was known about the inheritance of WFFS, Sternlicht was returned to breeding with the proviso of only mares testing N/N would be accepted for breeding.

5. What other genetic conditions are horses tested for?
Genetic testing within certain breeds is not new. A few common associations are listed below.

AQHA [6] - American Quarterhorse offers 5 panel testing for these disorders:
• HYPP: hyperkalemic periodic paralysis;
• PSSM1: polysaccharide storage myopathy;
• HERDA: hereditary equine regional dermal asthenia;
• MH: malignant hyperthermia; and
• GBED: glycogen branching enzyme deficiency; plus testing for
• IMM: Immune Mediated Myositis is also offered; not part of 5 panel.
Effective January 1, 2015 - All stallions are required to have a genetic disease panel test on file with AQHA prior to the registration of their foals.

AHA [Appendix B] - the Arabian Horse introduced an updated Code Of Ethics - January 2011 regarding 'Required Disclosure of Known Genetic Status Now Includes
• Severe Combined Immunodeficiency (SCID),
• Cerebellar Abiotrophy (CA),
• Lavender Foal Syndrome (LFS) and
• Hyperkalemic Periodic Paralysis (HYPP)
A 3 panel test is routinely used; additional testing can include OAAM: Occipitoatlantoaxial Malformation. Reporting is mandatory.

FHANA [7] - Friesian Horse - Testing for Hydrocephalus and Dwarfism is valid for Friesian horses and horses with Friesian ancestry.

GRP [8] - German Riding Pony stallions must now have DNA test results on file for CA (Cerebellar Abiotrophy), as well as Myotania if descending from any New Forest Pony lines. Carrier result status will not affect registration eligibility and will be recorded in the German VIT database. (2018)

6. What action did registries take once WFFS was reported?
Needless to say after publication of the Texas foal report, Warmblood associations world wide were closely monitoring the situation. Responses ranged from proactive recommendations to their breeders, to almost complete denial of a problem. It was the KWPN in 2018 that was very quick to issue statements and advise breeding members to voluntarily test their breeding stock, probably because the implicated stallion was theirs. The KWPN in Holland tested all stored samples of active stallions and made results public. [9]

In April 2018, Canadian Warmblood (CWHBA) issued a position statement on WFFS [Appendix A], as did numerous European registries. By late 2018, DNA testing was readily available in Europe. In North America at the same time, the lab at UC Davis offered a test to its registry partners, while private labs also offered testing. Only registry testing of stored samples was deemed parentage verified.

May 13, 2018 - Warmblood Studbook of Ireland (WSI) institutes Mandatory DNA-WFFS Testing for Stallions, Mares, and Foals, and publication of results. The proposed rules were overwhelmingly ratified by members in Referendum. Horses free of the WFFS gene to be awarded D-WFFS honorific.
This note below from Westfalen Breeding Director on the new DNA requirements for stallions [8]

Horse breeding does not only mean looking at the genetic abnormalities of a horse. There are many other factors that play a role in horse breeding and help to achieve the breeding goals. Incidentally, one should look at hereditary defects, but the stallion choice should not be based on it. It is not good to discriminate stallions only based on their WFFS status. WFFS is not the only gene defect that we know of. If you want to exclude all stallions with the various gene defects, then there will be no breeding stallions at any given moment. At present, the population with WFFS carriers is ten percent. We do not know whether this has been the percentage for some time, or whether this value increases exponentially. Fortunately, ten percent is still small enough that having public status is sufficient. Due to the mandatory specification of stallions and the breeders who have their mares tested, we are getting more results and we can observe how the genetic defect spreads in the future, and in case of necessity make a plan to influence it later. 
- Breeding Director Wilken Treu in an interview with Reiter Revue

7. Does Canadian Warmblood have a plan and testing in place?
During 2018, CWHBA worked closely with the Geneticists at Maxxaam Analytics (now BV Labs) to create a validated domestic test for Canadian breeders; in 2019 unveiled a test that could be parentage verified to ensure complete validity. To encourage testing and reporting, the test was offered members at a competitive rate.
CWHBA would like to come in line with the EU and those Warmblood registries in Europe and North America that, commencing 2019, mandated testing and publication of WFFS status. By assuring transparency of status, members can responsibly select an activated licensed and/or approved stallion.

8. What are the European regulations doing about reporting and testing for WFFS?
1/11/2018 - a new EU-Animal Breeding Regulation has been established. The German regulation of the ZVO (Zuchtverbandsordnung) will adjust accordingly. One of the new rules is the test for sires for the gene defect of WFFS (Warmblood Fragile Foal Syndrome). The new EU-Animal Breeding Regulation says that the consideration of health traits such as defects or irregularities is mandatory. The test for WFFS is implied in this statement.
Breeding associations need to point out the WFFS on their websites starting 2019 as the new regulations also affect the German breeding area. The ZVO requires a WFFS chapter to be included in the breeding program. In some small breeds, pony breeds, also cold bloods, there are also examinations for gene defects that have been going on for a longer period of time. The WFFS test compulsion for 2019 for riding horse stallions was initiated in September in a meeting of the Breeding Department of the German National Equestrian Federation (FN).

12/11/2018 - Breeding, Germany - The breeding department of the German Equestrian Federation held a special meeting in December to decide on some key issues for the breeding regulations of 2019. Re: WFFS: The German breeding regulations (ZVO) have to be adapted to recent changes to EU- animal regulations which included the mandatory testing for genetic defects. This means that as of 2019 the testing for Warmblood Fragile Foal Syndrome (WFFS) will be mandatory in Germany.
The warmblood breed societies will have to post the results on their website as of 1 January 2019. It will be allowed for WFFS positive stallions to continue breeding, but it is recommended for breeders to test their mares and not match positive mares to positive stallions. 

9. How does a horse get WFFS?
A horse 'gets' WFFS by inheriting the defective gene/s. The only way to get the lethal WFFS/WFFS is if both the sire and dam of the horse are carriers of WFFS. WFFS is not caused by a 'bug' and is not contagious.

10. What is the difference between 'having' WFFS and being a carrier?
Only a foal with two copies of the defective allele (version of the gene) 'has' WFFS. It has been hypothesized that a fetus who has WFFS could be reabsorbed or aborted. If a foal is born 'with' WFFS, he or she will show the signs and symptoms noted above, and will not be capable of life. 
A carrier has only one copy of the defective allele/gene, and one copy of the normal allele/gene. Carriers do not 'have' WFFS and are normal and healthy. There have been no formal studies of carriers and possible related health issues, but it is known that there are many international competitors who are carriers. 

11. Is WFFS really a disease?
Technically it is, because part of the definition of 'disease' is 'a disorder of structure or function ... not simply a direct result of physical injury.' WFFS is certainly a disorder of structure and function. But, it is not a disease the way most people think of a disease, like flu or E. coli or cancer. 
The clearer terms for WFFS would be syndrome, disorder, or genetic defect.

12. Is WFFS limited to warmbloods?
No.
While WFFS should probably be known as 'Fragile Foal Syndrome', because it has been identified not only in all Warmblood populations as well as in Trakehner and Thoroughbreds, the name will remain WFFS until the scientific community proposes a name change as that is how it was first described in literature. 
Early in 2018, UC Davis did a study of stored Thoroughbred DNA samples, and reported a 4% incidence. No individual animals were identified. Other studies have identified many different breeds also affected.

13. Is WFFS the same as HERDA?
No.
HERDA (hereditary equine regional dermal asthenia) is only similar in that it is an autosomal recessive genetic defect, but found in American Quarter Horses (especially cutting lines) and related breeds. Unlike WFFS, it manifests usually in the second year. As with WFFS, there is no cure but it is not necessarily lethal.
Although they are not the same, Dr. Nena Winand, who has studied both WFFS and HERDA, recommends 'testing any horses at risk for HERDA before breeding to Warmbloods, and not crossing carriers of these two disorders. Avoid crossing a mare that tested positive for the WFFS1 or the HERDA mutated gene with a stallion that tested positive for the WFFS1 or the HERDA mutated gene.' [from Q & A with Dr. Nena Winand on WFFS]

14. Can my horse get WFFS from another horse who is a carrier?
No. WFFS is not caused by viruses or bacteria and is not at all contagious. It is not a 'disease' in that sense; it is a genetic defect.

15. Do carriers get sick?
No, carriers do not get sick and will not show any outward signs of their carrier status. Being a carrier has no effect at all on the horses' phenotype (physical appearance). There are as many highly successful and international horses who are carriers as there are successful clear horses.

16. How do I know if my horse is a carrier (N/WFFS)?
Only by a DNA test that you can have done by submitting a hair sample.
Make sure to use a lab that is licensed and qualified to perform the test. The best option is to use the stored sample from CWHBA that has been parentage verified to confirm identity of the animal.

17. Should I test my riding horses?
Even if your horse is a carrier, it should have no effect on him or her, or the training or competition career. However, testing and reporting any horse contributes to the knowledge base on WFFS and its frequency and distribution in the population. The more complete the picture, the better the information we have to use and make breeding decisions.

18. How long has WFFS been around?
The scientist who discovered the mutation, Dr. Nena Winand, has speculated that the first mutation of the gene likely happened about 170 years ago. 

19. Do we know who the first horse was who had the gene mutation?
No. Identifying the horse who first had the mutation would require extensive retroactive research and pedigree tracking, from less than complete or necessarily accurate records, using only anecdotal suggestion of WFFS status. We may never know for sure who that 'original' horse was. Several researchers have tried and to date none have been proven.
For practical purposes today, that knowledge is irrelevant, since the mutation now exists in all Warmblood breeds and some other populations, including Thoroughbred & Trakehner.
Interestingly, a 2020 study was performed on a hypothesized origin horse, the Arabian stallion Bairactar Or. Ar. (1813), whose offspring in the 19th century were reported to have a similar phenotype. Genomic testing of DNA from a museum sample of Bairactar Or. Ar. showed that he did not carry the mutated allele. [10]
Likewise, another suspect was the Thoroughbred stallion Dark Ronald xx. Genomic study of preserved remains provided evidence that Dark Ronald was not the founder of the causative variant. [11]

20. What does WFFS mean for breeders?
WFFS is a topic of importance among breeders, because it will be breeders who will be managing WFFS by the decisions they make. Much of the current discussion of WFFS concerns these questions and decisions, and opinions vary a lot. Some breeders really believe that it's a big fuss over nothing. On the opposite extreme, some believe that every carrier should be removed from breeding. Each breeder needs to understand WFFS enough to make responsible breeding decisions for their program.

21. How many horses are carriers for WFFS?
Reports vary widely, but among Warmblood populations between 9 - 19% of horses are being reported as carriers of WFFS world-wide.

22. Can we stamp out WFFS?
It might be possible to stamp out WFFS, but it's unlikely. It would be necessary to remove every carrier from breeding, and that is unlikely to ever happen. The costs would be prohibitive, including the loss of valuable animals from the genetic pool of Warmbloods, and the cost to individual breeders of losing breeding animals. Also consider that every cross of a carrier (N/WFFS) on a clear (N/N) animal, has a 50% probability of producing a clear offspring.

23. Why are all known carriers not immediately taken from breeding?
There are several valid reasons to avoid removing all carriers from breeding. 

1) It would require the removal of something like 10% of the Warmblood gene pool from breeding. Genetic diversity is important, and among Warmbloods the diversity is not all that extensive to begin with so losing 10% could be noticeably detrimental to our genetic diversity. 
2) Genetic defects happen, and there are others in this population … new ones could develop. If you remove all carriers of all defects from breeding, you'd be looking at losing even more than 10% of your population from breeding. 
3) Not only would you be losing 10% of your breeding animals, you'd be losing some individuals that are extremely valuable in what they contribute to the improvement of sport horses.
The Westfalen Roemer, a Preferent stallion who stood at Iron Spring Farm and had a strong positive influence on the quality of dressage horses, was a carrier.  Proactively in 2018, the Canadian owner of the KWPN, SWB & CW approved Connaisseur declared that he is a carrier. [12] With the 2019 mandated declaration of status, it was noted that the International jumping sire Balou du Rouet is a carrier.
4) Removal of an animal from a breeding program means a significant loss for the individual breeder, in dollar cost, time and planning invested, with an immediate loss of productivity. Having to remove a mare out of your breeding program would be a significant loss for any breeder, and for a single mare owner it would be devastating. Having to remove more than one, or your best one, would mean an additional reduction of your business's value, with the loss of important future sales.

24. If we don't stamp out WFFS, how do we live with it?
Easily, and simply … by managing it! WFFS can be managed so that there is no risk of producing a foal with both WFFS genes: the lethal condition. An affected foal can only be conceived when both sire and dam are carriers. If breeders have a carrier mare, they must only breed her to stallions who are clear (N/N). A carrier crossed with a clear horse has a zero percent chance of producing an affected foal, and only 50% chance of being a carrier.
One popular line of thought from some breeders, is to continuing to breed this generation of mares and stallions, including carriers. Then choose non-carriers for breeding stock over the next generations … keeping preferably non-carrier fillies and for stallions, chose from the best sons preferably those who are non-carriers. This would be a gradual reduction of carriers among the breeding population.
This approach is supported by Dr. Nena Winand, one of the world's experts on WFFS.

25. Should carriers be 'culled'?
To clarify terminology, 'cull' is a term that means 'selectively slaughter.' A more accurate term in the context of WFFS would be 'remove from breeding.' 
To remove all carriers from breeding is not practical or advisable. According to Dr. Nena Winand, who has studies both WFFS and HERDA, 'Perhaps over time outstanding horses that are non-carriers can be sought out [for breeding] and the carrier frequency can be slowly reduced if necessary, but this type of change is best effected over many generations.'

26. Should I stop breeding my carrier mare?
This will be a very personal choice by the breeder with consideration of the genetic and bloodline contribution of that mare. While it is safe to breed a carrier mare to a clear stallion, individual breeders may wish to remove WFFS from the future generations they produce. To do that they would remove their carrier mares from their breeding program. If they then breed their clear mares only to clear stallions, their future generations will all be clear of the defect.

27. How do I find out if my mare is a carrier?
DNA testing is available in Canada, USA and European countries. Make sure to use a licensed and qualified lab for testing, and for CWHBA, use stored samples with BV Labs for parentage verification.

28. I have a carrier mare. Is it safe to breed her?
Absolutely yes, provided you choose a stallion that is clear of the defect (N/N). 'Safe' means that If you breed a carrier to a clear horse, you have zero chance of having an affected foal.

29. I want to breed my carrier mare but only to a clear stallion. How do I find out if a stallion is a carrier?
More and more information about stallion WFFS status will be published as more people become aware of its importance in breeding decisions - and as more mare owners ask for the information. Ask the stallion owner or the studbook the status of the stallion you are considering for your breeding program. Then make sure that status is defined in your breeding contract.
If the registry has not published the WFFS status of a stallion, and a stallion owner is not transparent about the carrier status of a stallion, that could be a red flag and mean that the stallion might not have been tested, and as such should be considered as if a carrier.

30. Is it possible to know if a stallion is a carrier if he's deceased?
Maybe. If the stallion has hair on file at a lab, that hair can be tested. If semen exists, BV Labs has a protocol to test semen remaining from a thawed straw. If both parents are known to be clear, the stallion would be considered clear. If the stallion has a carrier foal out of a proven clear mare, then he is a carrier.

31. I have a carrier stallion. Is it safe to use him?
Yes. When bred to mares that are clear, your stallion will never sire an affected foal. Some owners of carrier stallions are requesting proof of clear status from mare owners before they will sign a breeding contract.

32. Are there legal implications to be aware of with WFFS?
Legal advice is beyond the scope of this FAQ. Note though, that intentional deceit or lying is always legally questionable. However, there are a couple of examples that could be considered.

1) Hiding a stallion's carrier status: There was a 2016 successful Texas lawsuit filed against the owner (and others including the reproduction center) of a stallion who was a carrier for HERDA, similarly a genetic defect, claiming that the owner published a clear status for his stallion knowing he was a carrier. There was a significant out of court settlement by the stallion owner according to published reports and the case against the Veterinarian proceeded to trial. [13] [14]

2) European Union regulations: EU zootechnical regulations prohibit breeding a carrier to a carrier, if the genetic defect would cause the affected animal to suffer. i.e.: potential for a lethal foal.

33. My mare is clear (N/N) for WFFS. How can her foal be a carrier?
The only way that her foal can be a carrier is if the sire was a carrier. If you breed a clear horse to a carrier, you have a 50% chance of a clear foal, and a 50% chance of a carrier foal. To guarantee a clear foal, both parents must be clear.'

34. If my horse is clear, does that mean the parents are clear too?
No, not necessarily. If you breed a clear horse to a carrier, you will get a clear horse 50% of the time. So a clear horse could have two clear parents, one carrier parent, or even two carrier parents.
Even if two carrier parents were inadvertently bred, which had happened prior to publicizing of WFFS, 25% of their foals will be clear; 50% will be carrier; and the 25% chance of a lethal foal exists.

35. Why are so few foals born with WFFS?
Considering the percentage of breeding horses who are carriers of WFFS, we would expect one in every 400 Warmblood foals to be born with WFFS (in a population that is not managed for WFFS). The frequency has not been that high. The most likely reason is that foals with WFFS do not reach full term. The hypothesis is that they are reabsorbed or aborted, but no testing has been done to address this. 
The future of WFFS is in the hands of mare breeders, because they're the ones who will be making the breeding decisions. These FAQs are to help breeders learn as much as you can so you can make responsible breeding decisions that are right for your program.

36. Is mandatory testing and reporting something breeders want to see?
The sponsors of this motion believe that yes, mandatory testing and reporting of breeding stallions is important to breeders. Even a 25% chance of losing a breeding season and/or producing a dead foal is more risk than most breeders are comfortable with, when avoidance is so simple.
Breeder concern has been raised questioning why the status of stallions is not published for all stallions in the Stallion Directory.

37. Conclusion:
• Just as DNA record-keeping in many other breeds has helped control the risk of producing foals affected by crossing carrier to carrier of genetically recessive genes, so will identification of carriers of WFFS allow breeders make educated breeding decisions.
• Through mandatory testing and complete transparency regarding possible carriage of the WFFS gene, as our International colleagues have already mandated, breeders can have confidence and make better choices for their programs…. no breeder should ever again have to suffer the loss of a lethal foal.
• There should not be any 'hype' about having a carrier animal … the negative reactions that pervaded the industry in the early months of 2018, by and large became a non-event in Europe with the advent of mandatory testing of stallions.
• Just as CWHBA phased in available DNA testing programs to arrive at full parental verification in 2019, so can the association continue to grow by adding transparency with WFFS status by first starting with stallions. Then, with education, continue to expand the program to encourage testing of mares entering the population (especially those by a known carrier stallion) and testing of foals by/out of a known carrier parent.
Knowledge is power … knowing how to avoid this potentially lethal outcome should merely require adding this DNA test to our toolbox of better breeding practices and reporting all results.


APPENDIX:
A - Appendix-A_Statement-to-CWHBA_Members_regarding_WFFSV2
B - Appendix-B_Genetics_AHA_Code_of_Ethics - Arabian Horse Association

References:
1. https://www.eurodressage.com/2018/04/14/us-breeders-and-stallion-owners-alert-warmblood-fragile-foal-syndrome
2. Rüfenacht S et al, (2010) Swiss warmblood horse with symptoms of hereditary equine regional dermal asthenia without mutation in the cyclophylin B gene (PPIB). [Schweiz. Arch. Tierheilkd. 2010, 152, 188–192]. https://pubmed.ncbi.nlm.nih.gov/20361398/
3. Patent, Winand (2013); https://patents.google.com/patent/US20140186835A1/en
4. Monthoux, et al (2015) Skin malformations in a neonatal foal tested homozygous positive for Warmblood Fragile Foal Syndrome. https://pubmed.ncbi.nlm.nih.gov/25637337/
5. Aurich, et al (2019) Characterization of abortion, stillbirth and non-viable foals homozygous for the Warmblood Fragile Foal Syndrome https://www.sciencedirect.com/science/article/pii/S0378432019305597
6. https://www.aqha.com/-/dna-and-parentage-verification
7. https://www.animalgenetics.us/Equine/Genetic_Disease/Index.asp
8. https://westfalenverband.com/articles/NewDnaRequirements.html
9. https://kwpn-na.org/about/new-policy-for-stallions-regarding-warmblood-fragile-foal-syndrome-wffs/
10. Reiter et al (2020) Distribution of the Warmblood Fragile Foal Syndrome Type 1 Mutation (PLOD1 c.2032G>A) in Different Horse Breeds from Europe and the United States https://www.mdpi.com/2073-4425/11/12/1518/htm
11. Zhang X. et al (2020) Skin exhibits of Dark Ronald XX are homozygous wild type at the Warmblood fragile foal syndrome causative missense variant position in lysyl hydroxylase gene PLOD1 https://onlinelibrary.wiley.com/doi/full/10.1111/age.12972
12. https://www.eurodressage.com/2018/06/16/connaisseur-tests-positive-wffs-carrier
13. http://allaboutcutting.net/☛-lawsuit-against-stallion-owners-vet-regarding-herda-8-4-16/
14. https://casetext.com/case/minshall-v-hartman-equine-reprod-ctr

updated: March 31, 2021