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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, German Riding Pony, Half-Arabian, Hispano-Árab, Karabakh Horse, Lusitano, Mixed Breed, Part Bred Arabian, Shagya Arabian, Swedish Riding Pony, Unspecified
Description
Lavender Foal Syndrome (LFS), also known as Coat Color Dilution Lethal (CCDL), is a fatal autosomal recessive neurological disorder found in Arabian horses. Affected foals are often born with a diluted coat color that gives the condition its name. Birth is frequently difficult, and affected foals are usually unable to stand. They have episodes in which they rigidly extend their limbs, neck, and back. These episodes resemble seizures, and the foals do not appear normal between them. There is no treatment, and affected foals are typically euthanized within days of birth.
LFS is caused by a deletion in the myosin Va (MYO5A) gene, which was identified through a whole-genome association study in Arabian horses. Carrier frequency is highest in Egyptian Arabian bloodlines, where roughly 10% of horses carry the variant. The variant has not been detected in breeds without Arabian ancestry.
Carriers show no signs of the disorder, so DNA testing is the only way to identify them. Testing is recommended for any horse with Arabian ancestry, and it is also useful for horses of unknown pedigree. Screening breeding stock allows breeders to avoid pairings (n/LFS x n/LFS) that carry a 25% risk of producing an affected foal.
Possible results
| Genotype | Description |
|---|---|
| LFS/LFS | Affected: Horse has two copies of the LFS variant and is expected to develop signs of the disorder. |
| n/LFS | Carrier: Horse has one copy of the LFS variant and is not expected to show signs of the disorder. Each offspring has a 50% chance of inheriting the variant. |
| n/n | Clear: Horse does not carry the LFS variant and cannot pass it on to offspring. |
Breeds Affected
Arabian, Arabian Cross
Reference
[PMID: 20419149]