Severe combined immunodeficiency is characterized by T- and B-lymphocyte dysfunction resulting in a non-functional immune system. Affected dogs are predisposed to infections. The onset of signs typically occurs at 7 to 8 weeks of age and includes lethargy, poor growth, vomiting, diarrhea, ataxia, seizures, and blindness. Affected dogs rarely survive over 4 months of age. There is no treatment available for SCID.

Therapy is limited to symptomatic treatments for resulting infections and general supportive care. There is no cure.

There are many responsibilities to consider when breeding dogs. Regardless of test results it is important that your dog is in good general health and that you are in a position to care for the puppies if new responsible owners are not found. For first time or novice breeders, advice can be found at most kennel club websites.

This disease is autosomal recessive meaning that two copies of the mutation are needed for disease signs to occur. A carrier dog with one copy of the SCID mutation can be safely bred with a clear dog with no copies of the SCID mutation. About half of the puppies will have one copy (carriers) and half will have no copies of the SCID mutation. Puppies in a litter which is expected to contain carriers should be tested prior to breeding. Carrier to carrier matings are not advised as the resulting litter may contain affected puppies. Please note: It is possible that disease signs similar to the ones caused by the SCID mutation could develop due to a different genetic or clinical cause.