Important Updates for Owners and Breeders…Genetic Disorders

Like other species, horses can be affected by a variety of genetic diseases. Currently, there are ten testable equine genetic disorders, with three of these conditions associated with the Arabian breed (including the Egyptian bloodlines). As owners and breeders, it is important to be educated about these disorders and be aware of testing options that are available, so informed and responsible breeding decisions can be made to avoid producing affected foals. With tests available, there never needs to be another affected foal born again.

Genetic Testing and Education

Tests using mane or tail hairs with root bulbs attached are currently available for Lavender Foal Syndrome (LFS), Cerebellar Abiotrophy (CA) and Severe Combined Immunodeficiency (SCID. An option for combined testing for CA and SCID is now available. A veterinarian is not required to order these tests. Additional information on ordering tests can be found on the Arabian Horse Association (AHA) website at http://www.arabianhorses.org/education/genetic/docs/11Genetic_Testing_Information.pdf

 In addition, make sure to visit the updated and expanded AHA Genetics and Genetic Disorders page: http://www.arabianhorses.org/education/genetic/default.asp. An added feature to this special section is a dedicated forum in the AHA Online Community Forums where questions can be asked and valuable information is shared: http://secure.arabianhorses.org/forum/index.php?board=27.0.

Cerebellar Abiotrophy (CA) Project Update

Equine Cerebellar Abiotrophy (CA) is a debilitating degenerative condition of the cerebellar portion of the brain that results in a severe lack of coordination. The degree of severity can vary among individual horses, but most affected horses are euthanized before adulthood, due to the hazard they present to themselves and others, and the current inability to treat or cure the condition. Breeding experiments conducted at the UC Davis Veterinary Genetics Laboratory indicate that CA is the result of a recessive gene mutation, meaning both parents must contribute the “CA gene” in order to have an affected foal (this is the same mode of inheritance as SCID and LFS).

Research conducted at the UC Davis Veterinary Genetics Laboratory (VGL) by Drs. Leah Brault and Cecilia Penedo has identified a mutation that is associated with CA. This potential causative mutation involves two overlapping candidate genes that are undergoing further study. This is an important finding, as it moves the currently available CA test from a marker-based screening test to a more fully developed DNA test. The availability of this test continues to help diagnose the defect in suspect foals and to help owners identify carriers in their breeding stock.

The CA Project Update from the Arabian Horse Foundation and the UC Davis Veterinary Genetics Laboratory can be read in its entirety here: http://www.arabianhorsefoundation.org/news.html#ref1.

Thank you to Beth Minnich for providing this information. Beth serves as Chair of the Arabian Horse Foundation Research Advisory Panel and Chair of the AHA Equine Stress, Research and Education Subcommittee on Genetic Disorders.