Heterochromia

From Dog
Heterochromia[1]

Heterochromia is a common genetic abnormality of dogs characterized by different colored irises.

This disorder is caused by changes in iridal pigment concentration and distribution, characterized by at least two distinct and solidly colored areas or differently colored patches or spots. In some cases, it may be accompanied by thinning of the iris, or holes in the iris. Combinations of brown, blue and white are common.

Some cases can be attributed to disease or ocular traumaan injury. Heterochromia irides is seen in the Old English Sheepdog, Siberian Husky, American Foxhound, Alaskan Malamute, Dalmatian and Shih Tzu. In Dalmatians with heterochromia, approximately 20% have congenital deafness or reduced auditory responses as determined by brainstem auditory-evoked responses[2].

This condition is commonly observed in dogs with uveodermatologic syndrome[3].

Ocular disease may be found concurrently with this condition, including microphthalmia, cataracts, retinal dysplasia and optic nerve hypoplasia.

References

  1. Dogblog
  2. Holliday TA et al (1992) Unilateral and bilateral brainstem auditory-evoked response abnormalities in 900 Dalmatian dogs. J Vet Intern Med 6(3):166-174
  3. Sigle KJ et al (2006) Unilateral uveitis in a dog with uveodermatologic syndrome. J Am Vet Med Assoc 228(4):543-548