Naked Foal Syndrome

Gene: ST14

Transmission: Autosomal recessive

For an autosomal recessive genetic disease an animal must have two copies of the mutation in question to be at risk of developing the disease. Both parents of an affected animal must be carriers of at least one copy of the mutation. Animals that have only one copy of the mutation are not at risk of developing the disease but are carrier animals that can pass the mutation on to future generations.

Mutation: Substitution, ST14 gene; c.388 G>T, p.(E130 STOP), exon 4, chr.7.

Medical system: Cutanious

Breeds: Akhal-Teké

Age of onset of symptoms: At birth.

Naked Foal Syndrome is a recessive genetic disease that has been reported for more than 80 years in Akhal-Teke horses. The Akhal-Teke is a horse breed of Central Asian ancestry that is known for its endurance but also for its small breed population and as a consequent for its lack of genetic variation. Affected foals are born with alopecia and a mild ichthyosis, a phenotype with similarities to junctional epidermolysis bullosa seen in the Belgian horse. Most foals die within several weeks of birth although the exact cause of death is unclear. Molecular studies identified a mutation within the ST14 gene, whose protein product is involved in epidermal barrier formation and in hair follicle development. Studies of mutation frequencies in 191 Akhal-Teke horses revealed a carrier frequency of 13.6%. A genetic test will now allow breeders to identify carrier horses to be able to eliminate the disease and eventually the mutation from their animals through selective breeding.

References:

OMIA link: [2096-9796]

Bauer A, Hiemesch T, Jagannathan V, et al. (2017) A nonsense variant in the ST14 gene in Akhal-Teke horses with Naked Foal Syndrome. G3 (Bethesda). 7(4):1315-1321. [pm/28235824]

Contributed by: Abigael Lequin and Éloise Bédard-Sabourin, Class of 2028, Faculty of Veterinary Medicine, University of Montreal.