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LFS Lavender Foal Syndrome

Name: LFS Lavender Foal Syndrome
Brand: Equigerminal
Price: 43.05 EUR

Test that shows if your horse carries the gene change behind lavender foal syndrome, a deadly disease of Arabian foals....

€43.05 Mat TVA

About

This test shows whether your horse carries the gene change behind Lavender Foal Syndrome, an inherited condition that kills newborn foals.

It is a disease of Arabian horses, concentrated in Egyptian Arabian lines. Testing makes sense for any horse with Arabian blood and for any breeding animal whose pedigree is uncertain.

Why test?

Breeding. Two carriers can produce an affected foal. Knowing the result of both parents tells you what each mating can produce.

Buying and selling. The result is objective, permanent information you can show a buyer.

Investigating a lost foal. If the pale coat is missed, an affected foal is easily recorded as a dummy foal, as blood poisoning or as another newborn brain problem. Testing the foal, or the parents, settles the question.

Clinical signs

Signs are there from birth, and only in foals that inherited the change from both parents:

A washed-out coat colour, described as pale grey, pewter, light chestnut, silver or lavender. That is where the name comes from.
Fits, with the whole body going rigid and the head and neck arched backwards
Stiff or paddling movements of the legs, with the limbs held straight out
Eyes flicking rapidly from side to side, outside the foal's control
Unable to stand and suckle; lying down and not getting up
A slightly low white blood cell count in some foals

There is no treatment. Affected foals die, or are put down because they cannot stand or nurse, within about 72 hours of birth. The diagnosis is made by a veterinarian, combining the history, the examination and this genetic result.

Transmission

Lavender Foal Syndrome is recessive. A foal needs one copy from the sire and one from the dam to be affected. One copy makes a horse a carrier, never a patient. The gene is not on a sex chromosome, so colts and fillies are affected equally.

What each mating can produce:

n/n x n/n gives 100% n/n
n/n x n/LFS gives 50% n/n, 50% n/LFS
n/LFS x n/LFS gives 25% n/n, 50% n/LFS, 25% LFS/LFS

Prevention

Prevention is entirely a breeding decision.

Breeding. Test breeding stock before mating and never mate two carriers. A carrier mated to a partner that tested negative produces no affected foals.

Keeping valuable lines. Carrying the change is not a reason to leave a horse out of breeding. Mate a carrier only with partners that tested negative and test every foal. This keeps popular sires and valuable mares in use while the change is bred out.

Systematic testing of breeding stock is what lowers the number of carriers over time.

Results

n/n: negative. No copy of the LFS variant. Cannot pass it on.

n/LFS: carrier. One copy. Healthy, with a normal coat colour. Can pass the variant on.

LFS/LFS: affected. Two copies. The foal has Lavender Foal Syndrome.

Sample

Hair roots: 20 to 40 hairs pulled (not cut) from the mane or tail, with the roots attached. Tape them inside the marked area of the printable sample submission form. Hairs without roots cannot be analysed.

Blood: 5 mL of whole blood in a K3-EDTA tube, collected by a veterinarian. Label the tube with the horse's name and send it with the submission form.

Keep samples dry and at room temperature, and do not freeze them. Do not send hair that is wet, mouldy or soiled with bedding or faeces.

Turnaround

Standard processing: results within 5 to 10 working days of the sample arriving at the laboratory. Shipping is arranged and paid for by the client, and transit time is not included in the 5 to 10 working days.

Samples that fail DNA extraction or amplification are repeated at no extra cost, which may add a few working days. We contact you if a new sample is required.

How it works

🛒 Buy the test: select and buy the test online.

📧 Receive the instructions: after payment is confirmed, you receive the sample collection instructions by e-mail.

📄 Complete the form: print and complete the submission form with the animal’s identification.

✨ Collect the sample: pull 20 to 40 hair roots with the bulb and stick them in the marked area of the form, or ask your veterinarian to collect blood in a K3-EDTA tube.

📮 Send it to the laboratory: Equigerminal, S.A., HIESE, Rua da Quinta do Sobreiro, 25, Quinta Vale do Espinhal, 3230-343 Penela, PORTUGAL.

📊 Receive the report: the certified report is issued as soon as the analysis is validated.

FAQs

At what age can a horse be tested?
Any age. The genotype is fixed at conception and never changes, so one test lasts for life.

Does this test cover other Arabian foal diseases?
No. It does not detect SCID, Cerebellar Abiotrophy or anything else. A foal that tests negative for LFS can still have a newborn brain or nerve problem from another cause.

My report from another laboratory uses a different variant name. Is it the same test?
Yes. Some laboratories number the same deletion differently. The For Professionals tab gives both names.

For Professionals

Genetic and clinical detail for veterinarians, geneticists and laboratories.

Gene / locus: MYO5A (myosin VA), ECA1.
Variant: single-base deletion causing a frameshift and loss of the cargo-binding domain. HGVS (EquCab3.0): NC_009144.3:g.139290592del; XM_023617258.1:c.4249del; XP_023473026.1:p.(Arg1417Alafs*13). The affected protein region is identical in horse, human, mouse and rat.
Alternative designations: published as c.4459delC (Brooks et al., 2010) and as g.138235715delC on EquCab2.0. c.4459delC and c.4249del are the same deletion numbered against different reference transcripts; quote both when comparing laboratory reports. Laboratory allele symbol: LFS. Disease synonym: Coat Colour Dilution Lethal.
Variant identifiers: no rs/EVA identifier listed in OMIA; OMIA variant 510.
Variant classification: not currently evaluated (ISAG/AVCG, per OMIA).
Inheritance: autosomal recessive (OMIA code R); lethal in homozygotes.
Penetrance / expressivity: all seven affected foals in the discovery study were homozygous; all eight available parents and 16 of 23 other relatives were heterozygous (Brooks et al., 2010). Heterozygotes are phenotypically normal. The same deletion was found independently in South Africa and confirmed by a different method (Bierman et al., 2010).
Origin: the affected foals of the discovery study shared a common ancestor six to eight generations back; carriers were later found without that ancestor in their pedigrees, so the founder is probably older. The origin among Egyptian Arabian horses in Egypt was studied by AbouEl Ela et al. (2023).
Breeds with documented carriers or cases: Arabian (OMIA variant record), concentrated in Egyptian Arabian lines; part-bred Arabians at risk through Arabian ancestry. Not found in 78 Thoroughbreds or 30 Standardbreds (Brooks et al., 2010).
Allele / carrier frequencies: carrier frequency: 10.3% of Egyptian Arabians (6/58) and 1.8% of non-Egyptian Arabians (1/56), USA; three of these six carriers were breeding stallions (Brooks et al., 2010); 7 of 215 European Arabians (Gabreski et al., 2012); 13.3% of 203 South African purebred Arabians of the 2004/5 foal crop and 11.7% of 197 of the 2009/10 crop, attributed to strong Egyptian Arabian influence (Tarr et al., 2014). Over the same period, SCID carrier prevalence fell significantly after its test became available in 2005, while LFS and cerebellar abiotrophy, tested only from 2009 and 2011, showed no change (Tarr et al., 2014). Carrier surveys have also been published from Poland, Egypt and the wider Middle East and North Africa.
Clinical / diagnostic notes for veterinarians: affected neonates show seizures, opisthotonus, paddling or stiff limb movements and nystagmus, cannot stand or nurse, and have a dilute coat; pigment is produced but abnormally distributed in the hair shaft. If the coat is overlooked, LFS can be recorded as neonatal maladjustment, sepsis or other neonatal encephalopathy. Gross necropsy is unremarkable, so genotyping of the foal or both parents is the confirmatory test. No immunodeficiency is present, which helps separate LFS from SCID in Arabian foals. Comparative homologues: Griscelli syndrome type 1 (human; hypopigmentation with hypotonia and delayed motor development), dilute lethal mouse, dilute-opisthotonus rat.

Key references:

Brooks SA, Gabreski N, Miller D, Brisbin A, Brown HE, Streeter C, Mezey J, Cook D, Antczak DF (2010). Whole-genome SNP association in the horse: identification of a deletion in myosin Va responsible for Lavender Foal Syndrome. PLoS Genet 6(4):e1000909. doi:10.1371/journal.pgen.1000909. PMID 20419149.
Bierman A, Guthrie AJ, Harper CK (2010). Lavender foal syndrome in Arabian horses is caused by a single-base deletion in the MYO5A gene. Anim Genet 41(Suppl 2):199-201. doi:10.1111/j.1365-2052.2010.02086.x.
Gabreski NA, Haase B, Armstrong CD, Distl O, Brooks SA (2012). Investigation of allele frequencies for Lavender foal syndrome in the horse. Anim Genet 43:650. doi:10.1111/j.1365-2052.2011.02305.x.
Tarr CJ, Thompson PN, Guthrie AJ, Harper CK (2014). The carrier prevalence of severe combined immunodeficiency, lavender foal syndrome and cerebellar abiotrophy in Arabian horses in South Africa. Equine Vet J 46:512-514. doi:10.1111/evj.12177.
AbouEl Ela NH, El Araby IE, Saleh AA, Abd El-Fattah AH, Hagag NM, Brooks SA, Radwan MA, Kalbfleisch T (2023). Evidence for origin of lavender foal syndrome among Egyptian Arabian horses in Egypt. Equine Vet J 55:487-493. doi:10.1111/evj.13604.