Lavender Foal Syndrome (LFS)

Lavender Foal Syndrome

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Price: $40.00Price: £35.00

Breeds: Andalusian/Arabian, Anglo-Arabian, AraAppaloosa, Arabian, Arabian Cross, Arabian/Dutch Warmblood, Arabian/Friesian Cross, Arabian/Paint, Arabian/Pinto, Arabian/Quarter Horse, Arabian/Saddlebred, Arabian/Thoroughbred, Arabian/Warmblood, Egyptian Arabian, Half-Arabian, Hispano-Árab, Karabakh Horse, Lusitano, Mixed Breed, Part Bred Arabian, Shagya Arabian, Swedish Riding Pony, Unspecified


Lavender Foal Syndrome (LFS), also known as Coat Color Dilution Lethal (CCDL), is a recessive genetic disorder. Recessive genetic disorders are disorders that require two copies from both parents in order for the disease to be expressed. Affected foals often have a difficult delivery, problems standing at birth, and typically have episodes where they rigidly extend their limbs, neck and back. These episodes tend to resemble a seizure, although the affected foal does not seem normal between episodes. All affected foals are usually euthanized within days or weeks after birth.

The Onderstepoort Veterinary Genetics Laboratory found the mutation responsible for the genetic condition known as Lavender Foal Syndrome (LFS) in Arabian horses. They have developed a DNA-based test for this condition. Studies show that the prevalence of carriers in the Egyptian Arabian population is around 10%.

The mutation that causes LFS has not been detected in other breeds. Testing for this mutation in horses with no Arabian blood lines is not recommended, as there is no chance for them to have contracted LFS. However, in cases where pedigree is not known, testing could be a useful tool to prevent possible affected foals. It is important to test any horse with unknown lineage or known Arabian lineage in order to prevent two carriers from breeding with one another. If two carriers are bred, there is a 25% chance per foal that they will develop symptoms of Lavender Foal Syndrome.

Possible Results

Genotype Description
LFS/LFS Affected: Horse has two copies of the LFS gene mutation and will exhibit signs of the disorder.
n/LFS Carrier: Horse carries one copy of the LFS gene mutation. Horse has a chance to pass on this gene to any offspring.
n/n Clear: Horse is negative for the LFS gene mutation.


Whole-genome SNP association in the horse: identification of a deletion in myosin Va responsible for Lavender Foal Syndrome.

Brooks SA, Gabreski N, Miller D, Brisbin A, Brown HE, Streeter C, Mezey J, Cook D, Antczak DF. PLoS Genet. 2010 Apr 15;6(4):e1000909. doi: 10.1371/journal.pgen.1000909. [PMID: 20419149]