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Lavender Foal Syndrome (LFS)
| Acronym: | LFS |
| Gene: | MYO5A |
| Mutation: | g.138235715delC |
| Inheritance: | Autosomal Recessive |
| Sample type: | WBE (Whole Blood EDTA), HA (Hairs - with roots) |
Genetics and characteristics
Lavender Foal Syndrome (LFS) is an inherited neurological disease that affects the Arabian breed of horses, primarily of Egyptian descent. The coats of infected horses are described as a lavender-like colour and range from pale grey to light chestnut. Horses with LFS show numerous neurological signs of the disease, including involuntary muscle contractions and eye movements, hyperextension of the head and neck, and paddling leg movement. LFS is caused by a genetic mutation in the myosin 5A gene (MYO5A) responsible for the transport of pigment cells and various proteins and molecules within neurons. The small deletion in the MYO5A gene causes frameshift mutation that results in truncated protein which is not able to bind cargo for cell transport.
LFS is inherited as an autosomal recessive trait, so two copies of the mutation are needed for a horse to be affected. The disease is mostly lethal due to severe neurological symptoms. LFS affects only Arabian horses, one of the oldest and most influential breeds, which contributed to the development of many other breeds, such as Thoroughbred, Standardbred, Morgan, Quarter Horse, and Percheron. The disease is incurable, but early detection by genetic testing can help identify LFS carriers in the population and prevent further breeding.
Results Reported As
Test Result |
Interpretation of test result |
CLEAR |
Tested mutation was not detected in animal with „clear“ result. Animal tested as clear has wild-type allele in homozygous state (i.e. two pairs of healthy alleles). It will not develop disease caused by tested mutation.* It will pass only wild-type allele to its offspring. |
CARRIER |
Tested mutation was detected in animal with „carrier“ result. Animal tested as carrier has one wild-type and one mutation allele, it is in heterozygous state. It will not develop disease caused by tested mutation.* It can pass wild-type or mutation allele to its offspring. |
AFFECTED |
Tested mutation was detected in animal with „affected“ result. Animal tested as affected has two copies of mutation alleles affecting the gene. It is likely the animal will experience a genetic disorder due to this mutation.** It will pass only mutation allele to its offspring. |
*Test excludes only tested mutation but not possible unknown mutations or factors that can lead to similar condition/symptoms.
** Potential unknown mutations or multiple other factors can possibly affect the likelihood of experiencing a genetic disorder.
References:
Bellone, R. R. (2010). Pleiotropic effects of pigmentation genes in horses. Animal Genetics, 41, 100–110. doi:10.1111/j.1365-2052.2010.02116.x
Bugno-Poniewierska, M., Stefaniuk-Szmukier, M., -Kajtoch, A. P., Fornal, A., Piórkowska, K., & Ropka-Molik, K. (2019). Genetic screening for cerebellar abiotrophy, severe combined immunodeficiency and lavender foal syndrome in Arabian horses in Poland. The Veterinary Journal, 248, 71–73. doi: 10.1016/j.tvjl.2019.04.012
Gabreski, N. A., Haase, B., Armstrong, C. D., Distl, O., & Brooks, S. A. (2012). Investigation of allele frequencies for Lavender foal syndrome in the horse. Animal Genetics, 43(5), 650–650. doi:10.1111/j.1365-2052.2011.02305.x