Description
DNA test
Sample
- 5 mL - blood - K3 EDTA tube
Turnaround time
Why test?
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This 2 DNA tests for melanoma confirms if the grey horse is heterozygous (G/N) or homozygous (G/) for the Grey gene and if is Homozygous for non-agouti (a/a).The results can predict the type incidence for developing dermal melanomas.
Results description
The genetic profile test verifies the genotype of the Grey and Agouti genes, and presents results as one of the following:
Melanoma incidence risk
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G/N + A/a or A/A – Moderate incidence of dermal melanomas.
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G/N + a/a – Moderate to high incidence of dermal melanomas.
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G/G + A/a or A/A – High incidence of dermal melanomas.
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G/G + a/a – Very high incidence of dermal melanomas.
Additional information
Most melanomas found in horses are benign.
Once present these benign types of melanoma are not aggressive in their growth and may progress over several years requiring little treatment. A melanoma is one of the most common skin tumors seen in a horse or pony.
Grey horses have a high incidence of dermal melanomas that are commonly seen around the tail and head. Over 80% of Grey horses older than 15 years will develop melanoma.
Grey homozygotes are more likely to develop melanoma than heterozygotes.
Grey horses that are homozygous for non-agouti (aa) genotype at the Agouti locus, also have a higher risk for melanoma. Many Grey horses show depigmentation of the skin around the eyes, mouth and anus but there are no health risks associated with this condition.
Malignant melanomas in horses can cause severe problems and can be life-threatening. Problems develop when melanomas are present internally or if they become so large that they ulcerate, bleed and become infected.
Equine melanomas sometimes grow so large that they can cause severe weight loss and/or colic. If a melanoma is situated on the head in an area where a bridle, saddle, head collar or rug might rub, it will be uncomfortable for the horse, potentially causing behavioural problems. Infections can also occur.
