Ocular Squamous Cell Carcinoma (SCC)
Code: P385
Short description
Ocular Squamous Cell Carcinoma (SCC) is the most common eye cancer in horses, typically forming at the edge of the sclera (eye white) and arising in ocular surface.
General information
Ocular Squamous Cell Carcinoma (SCC) is the most common eye cancer in horses, typically forming at the edge of the sclera (eye white) and arising in ocular surface. Tumors can grow rapidly, causing visual impairment and eye destruction, but they rarely metastasize. The genetic predisposition for this disease is linked to a mutation in the DDB2 gene. Homozygous horses for this mutation are at increased risk to develop SCC compared to others. Additional risk factors include UV light exposure, horses with unpigmented areas around their eyes (such as white or pink eyelids), and those with chestnut-based coat colors, which are more susceptible. The variant analysed in this test is found in the Belgian Draft Horse, Connemara Pony, Haflinger, Appaloosa, Percheron, Rocky Mountain Horse, Gypsy Vanner, Tinker and Irish Cob.
Specifications
| Breeds | Gypsy Vanner, Irish Cob, Rocky Mountain Horse, Appaloosa, Belgian draught, Connemara Pony, Haflinger, Noriker, Percheron, Tinker, Warmblood, Welsh Pony |
|---|---|
| Gene | DDB2 |
| Chromosome | 12 |
| Mutation | c.1013C>T |
| Organ | Sensory organs |
| Specimen | Hair, Blood EDTA, Blood Heparin, Semen, Tissue |
| Mode of Inheritance | Risk Factor |
| Also known as | SCC |
Clinical features
Ocular SCC can develop in various regions of the eye, including the eyelids, sclera, conjunctivae (the thin pink tissue around the white of the eye), limbus (the junction of the cornea and sclera), and cornea (the clear front part of the eye). Symptoms vary depending on the affected area but may include redness, tearing, thick yellow ocular discharge, swollen scleral tissue, and the formation of tumors and lesions. When the upper and lower eyelids are affected, the early signs often appear as small, red areas that may look like burns, bleed intermittently, and form scabs. Treatment options and prognosis depend on the tumor’s size and location, with smaller lesions being easier to treat. However, many tumors are only detected once they have grown significantly. Prolonged presence of a tumor increases the likelihood of invasion into surrounding tissues, making treatment more challenging. Surgical removal is often necessary, and in cases of large or invasive tumors, removal of the affected eye may be required. Ocular SCC can lead to vision impairment or loss and, in severe cases, pose a significant threat to the horse’s life.
Additional information
The mutation in this test should be considered a risk factor. It is associated with the disorder, but does not necessarily guarantee it.
References
Pubmed ID: 28425625
Year published: 2017
Omia ID: 735
Omia variant ID:
Turnaround information
- 15 working days