Haflinger horses carrying certain bloodlines may be at increased risk for a specific type of eye cancer, according to a study from the University of California–Davis.

Researchers examined the medical records of 19 Haflingers at a university clinic who had been diagnosed with limbal squamous cell carcinoma (LSCC), an invasive tumor that develops on the limbus, the area bordering the eye’s cornea and sclera (“white”).

The average age of the horses at the time of diagnosis was 8.7 years. The researchers say there is an over-representation of the breed in LSCC incidence and a younger-than-expected age for LSCC development, which suggests that genetics play a role in this disease.

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Four-generation pedigrees were available for 15 of the study horses, and all traced back to a single prominent sire within the breed, providing further evidence that genetics are involved.

Two of the affected horses had the same sire, who himself showed no clinical signs of LSCC, suggesting a recessive mode of inheritance, according to the researchers. They call for further investigation of a genetic basis for LSCC in Haflingers.

Reference: “Limbal squamous cell carcinoma in Haflinger horses,” Veterinary Ophthalmology, October 2014 

This article first appeared in EQUUS issue #448,

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