Break Through in Horse Breaking Trauma!

A recent discovery has identified the mutation that causes hereditary equine regional dermal asthenia (HERDA), formerly known as ‘hyperelastosis cutis’ (right). This degenerative disease found primarily in Quarter horses is untreatable and is carried by 3.5% of Quarter horses. As foals there is no clinical signs of the disease until a mean age of 1.3 years, where blisters, ulcers and lacerations often form from irritation from the saddle.

The first time that the entire horse genome was used, allowed the use of gene specific markers in comparing genomes of affected horses. An identical homozygous portion was found to be in descendants of affected horses. This homozygous mutation has been reported in cyclophilin B(PPIB) as the genetic cause for HERDA.

Before now there has been no diagnosis for the disease until the age of breaking, when saddling initiates the disorder. Because of this the breeders are often unaware of their stock carrying this debilitating disease, as the offspring are usually sold before being broken in.

As an Autosomal recessive trait, the joining of two carrier parents produces young with a 25% chance of being affected. Research has shown that out of 64 affected horses, 11 were inbred, demonstrating where the problem has originated. The discovery of a diagnostic test using DNA analysis is therefore useful in determining carriers of the trait, to prevent breeding and inbreeding of these horses.

This rare inherited disease of Quarter horses, should be a progressively solvable problem, by providing the use of DNA analysis testing.

Posted by Demelza Mitchell
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Links:
Research paper one
News report
mutation research
News report 2
Horsetalk report