|Affected breeds:||Quarter Horse and related breeds|
|Description:||Hereditary Equine Regional Dermal Asthenia Genetic Testing
This test detects a single basepair change in exon 1 in the Peptidylprolyl Isomerase B (PPIB) (or Cyclophilin B) gene.
|Time:||10 – 14 days|
Hereditary Equine Regional Dermal Asthenia (HERDA)
excl. 19% VAT
→ Skin detachment causing severe lesions and ulcerations.
Instructions for ordering:
- Enter the information of the first horse for which you want to order the test
- Add to cart
- Go to cart to check out, or
- Enter the information for a second horse
- For sample collection follow the instructions here.
- You can use this template to send in hair samples.
- Please also send the completed order form together with the samples.
For a breeder or veterinarian discount please contact us before ordering.
Any information you include here is optional, but will be included on the certificate of results (except “Additional info”).
- First symptoms may be seen at the age of 1,5 years after horses are under the saddle.
- Areas under pressure (saddle, etc.) are particularly affected, and the skin trauma is difficult to heal.
- Affected horses are usually euthanized due to poor quality of life.
- Defect in the connective tissue results in skin splitting, tearing and separating from underlying layers.
- Loose sloughing skin
- Lesions and ulcerations/cysts especially in dorsal area
- Slow healing
Inheritance and Genotypes
→ HERDA is an autosomal recessive hereditary disease, meaning that horses with only one copy of the genetic variant (N/herda) are clinically normal carriers while horses with two copies of the genetic variant (herda/herda) are affected.
|Genotype:||The horse is:||Effects:|
|N/N||normal.||The horse does not have any copies of the genetic variant causative for HERDA and therefore cannot pass it on to any offspring.|
|N/herda||a carrier.||The horse is clinically healthy. The genetic variant causative for HERDA will be passed on to its offspring with a probability of 50%.|
|herda/herda||affected.||If the horse lives long enough to reproduce, the genetic variant causative for HERDA will be passed on to all offspring. All offspring will be clinically normal carriers (N/herda).|
- Carriers may be bred to normal animals (N/herda x N/N) without any risk of producing affected offspring. The offspring should also be tested before breeding to determine if they are carriers or normal.
- Breeding two carriers (N/herda x N/herda) is not recommended due to the possibility of 25% of the offspring being affected.
- Affected animals (herda/herda) should not be used for breeding.
Tryon RC, White SD, Bannasch DL. Homozygosity mapping approach identifies a missense mutation in equine cyclophilin B (PPIB) associated with HERDA in the American Quarter Horse. Genomics. 2007 Jul;90(1):93-102. DOI: 10.1016/j.ygeno.2007.03.009.
Further information is available at Online Mendelian Inheritance in Animals.