Investigations of Ocular Melanosis in Cairn Terriers

Research Report 4/2002

Simon Petersen-Jones


Assistant Professor, Comparative Ophthalmology

Dept. of Small Animal Clinical Sciences

Michigan State University

D-208 Veterinary Medical Center

East Lansing, MI 48864-1314

Aims for our studies

These remain the same as for my previous reports:

  1. Completely characterize the disease, Ocular Melanosis, so that we know all the variations of the disease and the range of ages at which dogs can develop the lesions of Ocular Melanosis.
  2. Prove beyond doubt the mode of inheritance of Ocular Melanosis.
  3. Identify the genetic defect that causes Ocular Melanosis and develop a DNA test for that mutation. Identify the most effective treatment for dogs that do develop the condition.


We now have 145 DNA samples from Cairn Terriers either with Ocular Melanosis or closely related to dogs with Ocular Melanosis. We have pedigree information on all of the dogs except for one or two where pedigrees were not available. Our pedigrees have been drawn up into large pedigrees linking affected dogs to help us better analyze the mode of inheritance. We still cannot conclusively prove a mode of inheritance (although we can exclude certain modes). Gathering information about the status of all other members of litters in which there is an affected dog would be helpful. The later age at which OM is often diagnosed makes this more difficult. We have been investigating a gene that is known to cause a similar disease to OM in mice. We are looking for polymorphisms (gene variations) in the gene in Cairn Terriers. We can then use the polymorphisms to see if the gene is associated with the OM. We have recently identified a polymorphism and we are in the process of looking to see whether this can be used to see if this particular candidate gene is likely to be the site of the gene mutation that causes OM. It will take a few months to complete this work.

Further funding

To enable more progress to be made we will need more substantial funding. I have twice applied to the Morris Animal Foundation, but although they have funded me for a different project they do not seem interested in funding the OM research. If a genone-wide scan is also required it might be sensible to seek funding from the AKC-Canine Health Fund, although they would require matching funds from your Foundation and I am aware that you have other health issues that require funding.