There is a well described syndrome of epilepsy in young Arabian foals of Egyptian lineage. Seizures are usually noticed by 2 months of age (range of 2 days through 6 months), are generalized, and usually lasts for less than a minute, although some may last up to 5 minutes. Post-ictal (post-seizure) signs are marked and include dullness, loss of interest in the mare and no interest in feeding, and blindness. The blindness is typically the last sign to resolve and may persist for hours, days or even weeks. Affected foals respond positively to anti-seizure medication for a minimum of 3 months. Untreated foals also may grow out of the problem by around a year of age, although they are susceptible to seizure-related injuries and possibly long-term behaviour problems.
A genetic link has been suspected and this study identified a specific genetic variant in affected foals. For those with knowledge of genetic mutations there was a single 19bp deletion and a triple-C insertion within the TRIM39-RPP21 gene. The authors indicated that further work is needed to validate the gene as a marker in affected foals. Once definitively established the hope would be to examine whether the genetic mutation is present in other breeds of Arabian heritage.
This was a multi-institutional study based out of the Koret School of Veterinary Medicine in Israel.
Sequence Variant in the TRIM39-RPP21 Gene Readthrough is Shared Across a Cohort of Arabian Foals Diagnosed with Juvenile Idiopathic Epilepsy by Polani and others. Published in the Journal of Genetic Mutation Disorders. This is an open access journal and the link to the article can be found here.