A genetic variant of the PAX3 gene (DBE-re) has been identified as the cause of the dominant blue-eye phenotype in Maine Coon cats. This variant affects iris pigmentation and is also associated with unilateral or bilateral deafness and minimal white spotting that is not explained by the known white-spotting variants.
The trait shows incomplete penetrance, and recent findings indicate that some cats may carry the variant without expressing blue eyes. There is also evidence that homozygosity for the DBE-re allele is embryonic or foetal lethal, and therefore mating two heterozygous carriers is strongly discouraged.
A genetic test can determine whether the blue-eye phenotype is due to this specific PAX3 variant.
This test detects only the DBE-re variant.
