Congenital short tail (Bob Tail / Short Tail/ Brachyury) – NBT
Naturally occurring short-tailed dog


Description: The genetic cause of the congenitally short tail was first described in 2001 in Pembroke Welsh Corgi breed. A mutation in the T-box of the transcription factor T gene (c.189C> G) was identified as a causal mutation causing the phenotypic expression of the short tail. Further research confirmed the identical molecular reason of the natural short tail NBT (natural bobtail) in 17 other breeds (Hytonen et al. 2009). In individuals carrying a mutation in the T gene, the tail length is naturally shortened but may vary considerably. Some individuals lack the tail completely and some may have it cut in half.

The mutation is autosomal dominant, i.e. individuals with a short tail carry the mutation in a heterozygous state. The mutation in a homozygous state is lethal during the embryonic period (in utero), and causes a cleft spine (spina bifida). After mating of two heterozygous individuals showed a 30% loss of puppies per litter (Haworth et al. 2001; Indrebø et al. 2007).

The relationship between the presence of the mutation and the short tail has been established only in selected breeds and is therefore not suitable for all breeds in which a genetically conditioned short tail is present.


Inheritance: autosomal dominant


Mutation: c.189C> G in T-box gene


Sample: EDTA whole blood (1.0 ml) or 2 buccal brushes. For official purposes, the confirmation of the dog’s identity by Veterinarian is recommended.
The analysis is suitable for the following breeds: Australian Shepherd, Austrian Pinscher, Australian Stumpy Tail Cattle Dog, Bourbonnais Pointer, Brazilian Terrier, Brittany Spaniel, Croatian Sheepdog, Danish / Swedish Farm Dog
Jack Russel Terrier, Karelian Bear Dog, Mudi, Polish Lowland Sheepdog, Pyrenean Sheepdog
Savoy Sheepdog, Schipperke, Spanish Waterdog, Swedish Vallhund, Welsh Corgi

Notes: In the other six breeds characterized by the occurrence of a naturally short tail, the c.189C> G mutation was not found. In these breeds, the determination of the genetic nature of the short tail are being investigated. This test is not recommended for breeds Boston Terrier, English Bulldog, King Charles Spaniel, Miniature Schnauzer, Parson Russel Terrier, Rottweiler