Cutaneous lupus erythematosus (CLE) is a localized skin disease that occurs in a few canine breeds, but the mode of inheritance has yet to be completely described. For some time, it has been believed that exfoliative CLE has a heritable form present in German shorthaired pointers. Most dogs develop this disease before 10 months of age and both males and females develop the disease in equal proportions.
Studies of human patients with CLE have identified multiple genes and chromosomal regions that contribute to disease. In human disease, all associated genetic components are also involved in immune pathways, inflammation, and cell death, the early complement cascade, type I interferons, toll-like receptors, STAT4 and MHC II proteins.
Genome-wide association studies (GWAS) have been utilized to further describe CLE in humans and dogs. Researchers applied a GWAS to further investigate the genomic region responsible for ECLE in German shorthaired pointers in an effort to improve genetic lines and ideally remove the trait from the breeding pool. Similarly, findings from animal studies could inspire further study of the genomics involved in cases of human CLE.
It has been determined that the defective gene that leads to this disease in dogs is homologous to the gene region that is affected in human patients with CLE.
Based on GWAS analysis, six genes were identified as potential genes responsible for exfoliative CLE in German shorthaired pointers. Further sequence variation determined that a single DNA base substitution of guanine (G) to adenine (A) was present in affected dogs and absent in unaffected animals. Affected dogs were homozygous for the A allele, obligate carriers were heterozygous (AG) and normal (unaffected) dogs were homozygous for the G allele.