Genetic Health Testing for Arabian Horses

Arabian horses, known for their beauty, stamina, and intelligence, are among the top ten most popular horse breeds in the United States. However, like any breed, they can be predisposed to certain genetic health conditions. Some conditions that may occur in Arabian horses that are worth DNA testing for include:

Severe Combined Immunodeficiency (SCID)

SCID is a genetic disorder that affects the immune system, leaving affected foals unable to produce functional T and B lymphocytes. Without a functional immune system, affected foals are highly susceptible to infections and typically do not survive beyond a few months without intensive medical intervention. This disease has only been found in Arabian horses, and about 8% of Arabian horses are carriers of the SCID allele. SCID is always fatal in horses, usually within 4-6 months of birth. It is a recessive trait, which means a horse needs to inherit two mutant alleles (SCID/SCID) to get the disease. Horses with just one mutant allele (SCID/n) are typically healthy but are 'carriers' who can pass the mutation to their offspring. If two carrier horses breed, there's a 25% chance their foal will have SCID. This is why it is important to know your Arabian’s genetic SCID status if you intend to breed them as they may carry the variant without you ever knowing.

Lavender Foal Syndrome (LFS)

This is a genetic neurological disorder that affects Arabian foals. LFS is also known as coat color dilution lethal and produces a diluted coat color that ranges in shade from silver to a pale lavender/pink. It typically presents within a few days of birth and is characterized by seizures, severe hyper-extension of limbs, neck and back, stiff paddling leg movements, involuntary eye movement, and the inability to stand or sit upright. Unfortunately, affected foals usually do not survive beyond a few weeks. Like SCID, LFS is a recessive condition, thus a horse must inherit two copies of the allele (LFS/LFS) to show any signs. Horses with only one copy of the allele (LFS/n) are known as carriers due to their ability to produce affected foals.

Cerebellar Abiotrophy (CA)

CA is another neurological disorder seen in Arabian foals. It causes progressive degeneration of the cerebellum, leading to symptoms such as incoordination, tremors, and difficulty standing. Affected foals usually show signs within the first few months of life, typically between six weeks and four months of age. Similar to SCID and LFS, CA is also a recessive condition, so a horse must be homozygous for the allele (CA/CA) to show any signs. Heterozygous horses with only one copy of the allele (CA/n) are carriers and have the ability to produce affected foals.

Occipitoatlantoaxial Malformation Type 1 (OAAM1)

This condition involves abnormalities in the formation of the vertebrae at the base of the skull and neck. It can lead to compression of the spinal cord and neurological deficits. OAAM may cause symptoms such as abnormal head and neck movements that may also make a clicking sound, ataxia, weakness, and in severe cases, paralysis. OAAM is another recessive health defect found in Arabian horses, meaning a horse needs to be homozygous for the variant (OAAM1/OAAM1) to be affected, whereas heterozygous (OAAM1/n) horses are carriers with the ability to pass the variant on. Type 1 is currently the only form associated with a specific genetic test at this time. It is believed that other genetic mutations are involved with OAAM and that it may be found in other breeds of horses. This means that even though a horse may test negative for OAAM1, that does not necessarily mean they do not have another form of OAAM that is not currently associated with a genetic test.

Because many of these specific health conditions are recessive, they may not directly impact your Arabian if they are a carrier. This does mean, however, that you should plan to DNA test your Arabian if you plan to breed them to ensure they do not pass on any of these potentially fatal health conditions to their offspring. With our one-of-a-kind Health Panel DNA test package, you can get to know your Arabian down to their DNA and find out if they carry any of these genetic health conditions and so much more!