Severe combined immunodeficiency disease (SCID) in Jack Russell Terrier

Severe Combined Immunodeficiency Diseases (SCID) is a serious inherited disease affecting the immunity of the organism. Affected individuals are extremely susceptible to a wide range of pathogens.

In Jack Russell Terriers, the disease is caused by a mutation in the gene for the DNA-PKcs enzyme. It is a point mutation (g.49588C>A) that results in premature inclusion of the stop codon. The result is a dysfunctional allele.

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 prevent unintentional breeding of affected puppies.

.

References:

Bell, T.G., Butler, K.L., Sill, H.B., Stickle, J.E., Ramos-Vara, J.A., Dark, M.J. : Autosomal recessive severe combined immunodeficiency of Jack Russell Terriers Journal of Veterinary Diagnostic Investigation 14:194-204, 2002. Pubmed reference: 12033674