Dog leukocyte antigen

The dog leukocyte antigen (DLA), part of the major histocompatibility complex (MHC) in dogs, plays a critical role in the immune system by encoding genes that regulate antigens. The MHC consists of three regions: class I, II, and III, with DLA genes belonging to classes I and II. Class II genes are highly polymorphic, linked to diseases like diabetes, allergies, and autoimmune conditions such as hypothyroidism.

The DLA region likely contains hundreds of immunologically relevant genes, many of which remain uncharacterized. MHC/DLA alleles vary significantly between dog breeds due to selective breeding for specific phenotypes, leading to limited genetic diversity within breeds. This has increased the prevalence of immune-mediated diseases in some breeds.

Canine diabetes is associated with specific DLA alleles: DLA-DRB1*009, DQA1*001, and DQB1*008. These alleles are common in breeds prone to diabetes, such as Samoyed, Miniature Schnauzer, and Standard Poodle. The DQA1*001 allele is linked to susceptibility, while DQA1*002 is protective. Genetic testing for these haplotypes aids in understanding disease risk.

The text also highlights the importance of DLA diversity among indigenous dog populations, as shown by studies in Indonesia, Australia, and Papua New Guinea, which reveal unique genetic relationships. However, expanded SNP genotyping has led to spurious associations, emphasizing the need for careful interpretation of genetic data.

Overall, the DLA's role in immune response and disease susceptibility underscores the importance of genetic diversity in managing health issues in dogs.