The diversity of the maternal and paternal haplotypes in the Major Histocompatibility Complex (MHC) region of the genome has been found in some studies to be associated with the incidence of certain autoimmune diseases.
Dogs that have less diversity in the MHC region haplotypes (i.e. the Dog Leukocyte Antigen (DLA) inherited from the mother is similar to the DLA inherited from the father) are considered less immunologically diverse.
- High Diversity means the dog has two highly dissimilar haplotypes.
- Low Diversity means the dog has two similar, but not identical, haplotypes.
- No Diversity means the dog has inherited identical haplotypes from both parents.
There is still much to learn about MHC/DLA in dogs, and more structured studies published in peer-reviewed journals are needed to draw any specific conclusions. The MHC genes help in identifying the dog's own tissue as well as the identification and elimination of foreign pathogens. Variability appears to be crucial to these immune genes, enabling them to react to different viruses, bacteria, and other foreign intruders. However, the veterinary scientific community is still working to figure out which of the various DLA types are present more often in dogs suffering from common diseases with an immune component, and if there is a link between their presence and development of the disease.