American Paint Horses with certain coat patterns and blue eyes appear to be at particular risk for deafness, reported researchers from the School of Veterinary Medicine, University of California-Davis.

"Deafness is infrequently recognized in horses. While there are a variety of mechanisms by which a horse can become deaf, there is little information regarding the possibility that a genetic mutation that causes spotted coat colors may also result in hearing impairment," explained study co-author K. Gary Magdesian, DVM, Dipl. ACVIM, ACVECC (emergency and critical care).

Genetic mutations that cause specific coat colors and hearing impairment have been identified in dogs, cats, and other species.

"To investigate whether coat color patterns were associated with deafness in American Paint Horses, we compared clinical findings, hearing test results (a brain auditory-evoked response test), and genotype of the endothelin B receptor gene (linked to a specific overo coat pattern) in both confirmed and suspected deaf American Paint Horses and nondeaf American Paint Horses and Pintos," relayed Magdesian