|Mutation:||chrX:55484657-55484660: 4 bp deletion (del CCTC)|
X-linked severe combined immunodeficiency (basset hound type) is an inherited disease affecting basset hounds. Affected dogs are unable to produce a protein important for proper immune function, predisposing them to severe recurrent or chronic bacterial, viral and fungal infections. Affected dogs often present with symptoms of disease around 6 to 8 weeks of age including failure to thrive, poor growth, weight loss, lethargy, diarrhea, vomiting and lack of palpable lymph nodes. Affected dogs may also present with active respiratory, skin, eye or ear infections. Affected dogs die within 4 months of age.
Genetic testing of the IL2RG gene in basset hounds will reliably determine whether a dog is a genetic Carrier of X-linked severe combined immunodeficiency (basset hound type). X-linked severe combined immunodeficiency (basset hound type) is inherited in an X-Linked Recessive manner in dogs meaning that female dogs that have one copy of the Mutation are carriers. Female dogs must receive two copies of the mutated gene (one from each parent) to develop the disease while male dogs only require one copy of the mutated gene from the mother in order to develop disease. Therefore, male dogs more commonly present with symptoms of the disease. Each male pup that is born to a female dog known to be a carrier of X-linked severe combined immunodeficiency (basset hound type) has a 50% chance of inheriting the disease. Reliable genetic testing is important for determining breeding practices. Because female carriers generally do not have features of the disease, genetic testing should be performed before breeding. In order to eliminate this mutation from breeding lines and to avoid the potential of producing affected pups, breeding of known carriers is not recommended. Basset hounds that are not carriers of the mutation have no increased risk of having affected pups.
There may be other causes of this condition in dogs and a normal result does not exclude a different mutation in this gene or any other gene that may result in a similar genetic disease or trait.
- Henthorn PS, Somberg RL, Fimiani VM, Puck JM, Patterson DF, Felsburg PJ. IL-2R gamma gene microdeletion demonstrates that canine x-linked severe combined immunodeficiency is a homologue of the human disease. Genomics. 1994 Sep 1;23(1):69-74. [PubMed: 7829104]