Exfoliative cutaneous lupus erythematosus in German Shorthaired Pointers and Vizslas

This disease is characterised by scaly and crusty skin lesions that occur initially on the face, ears and back but gradually spread over the whole body. The first symptoms usually appear by ten months of age. In later stages, the disease can become systemic and affect other organs - lupus nephritis, joint pain or infertility may develop. Secondary infections are common.

The cause of the disease is a missense mutation c.1438C>A in the UNC93B1 gene, which mediates the transmission and correct localization of toll-like receptors (TLRs), which are able to recognize foreign structures and are a part of the innate immune response. Loss of function of this gene results in severe immune deficiency.

The mode of inheritance of the mutation is autosomal recessive. This means that only individuals who inherit the mutated gene from both parents will develop the disease. Carriers of the mutated gene are clinically healthy but pass the mutation on to their offspring. In the case of a mating between two heterozygous individuals, theoretically 25% of the offspring will be completely healthy, 50% of the offspring will be carriers and 25% of the offspring will inherit the mutated gene from both parents and will therefore be affected by the disease.

The genetic test can clearly reveal the genotype of the animal and is a useful tool for breeders to avoid unintentional breeding of affected puppies.

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References:

Leeb, T., Leuthard, F., Jagannathan, V., Kiener, S., Letko, A., Roosje, P., Welle, M.M., Gailbreath, K.L., Cannon, A., Linek, M., Banovic, F., Olivry, T., White, S.D., Batcher, K., Bannasch, D., Minor, K.M., Mickelson, J.R., Hytönen, M.K., Lohi, H., Mauldin, E.A., Casal, M.L. : A missense variant affecting the C-terminal tail of UNC93B1 in dogs with exfoliative cutaneous lupus erythematosus (ECLE). Genes (Basel) 11:159, 2020. Pubmed reference: 32028618