Summary: TNS is a disease affecting the immune system of affected Border Collies. This disorder is caused by a mutation trapping white blood cells in the bone marrow, as opposed to being released into the bloodstream to perform normal immune functions. As expected, dogs with this disease will experience frequent infections and possible developmental delays. There is currently no known treatment for TNS outside of supportive care and the prognosis for affected dogs is poor.

Screening: Screening is available through many genetic testing companies around the world. The disease is a recessive mutation, meaning two mutant copies are required for a dog to be affected with the disease.

Inheritance: Recessive

Ethical breeders shall perform necessary genetic testing and not breed dogs that can produce affected puppies (ie. carrier to carrier OR carrier to affected)