DNA test – T-box (bob tail)

Details about the disease

T-box causes dogs to be born with shorter tails (or bob tails) compared to dogs that carry no copies of the gene, and causes neonatal death in dogs carrying two copies.

Clinical signs

Dogs with one copy of the gene are born with a shorter tail, which ranges from being a couple of centimetres, to being a quarter of the length compared to dogs born with full tails. There are no known health concerns associated with having one copy of the gene, but puppies carrying two will likely die prenatally, and if born suffer from severe deformities and die during, or shortly after birth.

How is it inherited?

The abnormal copy of the gene behaves as autosomal dominant in respect to bobtail, and as autosomal recessive in respect to neonatal death. This means that a dog must inherit two copies of an abnormal gene (one from its mother and one from its father) before its health is affected, but only one copy is required to shorten the tail.

Which laboratories we record and publish the results from?

To find out which laboratories The Kennel Club is able to record results from, and which laboratories will send results directly to The Kennel Club, please refer to our website.

Please be aware, The Kennel Club has a set of criteria that we request DNA testing laboratories to meet to enable us to record their results, helping to maintain and protect the integrity of results that appear on a dog’s record. We strongly advise that customers ensure their chosen laboratory is included on our list if they wish The Kennel Club to record and publish the results. Results from laboratories not included on this list will not be recorded.

Breeding advice and what your dog's results mean

If, once your dog is DNA tested, you would like to find out what their DNA test results mean, or how to select the right mate to avoid producing affected puppies, then please read our breeding advice and DNA testing information.

How to find out if a potential mate has been DNA tested

The Kennel Club’s on our Health Test Results Finder allows you to find the results of DNA tests carried out as part of The Kennel Club's official DNA testing schemes for any dog on The Kennel Club’s Breed Register.