Several studies have shown that Mhc genotypes are associated with protection or increased risk of inflammatory disease, including chorioretinitis in humans, upon exposure to different parasites. A major selective force to maintain high degree of Mhc polymorphism is considered to be parasite-driven. Thus, development of chorioretinitis in FCRs could be associated with Mhc, which in dogs is called Dog Leukocyte Antigens (DLA). To investigate such potential genetic association a pilot study of DLA class II association to chorioretinitis among FCRs has been initiated.
Current results indicate that homozygosity of the DLA class II haplotype “DLA-DRB1*01501/ -DQA1*00601/-DQB1*02301” is increased among dogs with chorioretinopathy and may thus increase the risk for development of this disease. To conclude that Mhc is a genetic risk factor for this form of retinal degeneration requires analysis of DLA class II in a larger case-control population and results from such a study will be reported.