Screw Tail (DVL2)

Test Overview:

A shortened and kinked tail—which is referred to as a “screw tail” — is one of the distinctive morphological traits that characterizes Bulldogs, French Bulldogs and Boston Terriers, which were historically developed from the Bulldog breed and, thus, closely related breeds. The ‘screw tail’ is caused by a variety of malformed and fused vertebrae and lack of approximately 8 to 15 caudal vertebrae.n addition to the Dvl2 frameshift mutation, the three Bulldog related breeds harbor other mutations in developmentally important genes that could affect their craniofacial morphology.


Trait (Associated with Phenotype)



Variant Detected:

frameshift mutation in the WNT pathway gene DISHEVELLED 2 (DVL2) (Chr5: 32195043_32195044del, p = 4.37 X 10?37)


It is a trait and so is tested based on preference, not usually for health concerns.

Mode of Inheritance:

Autosomal Recessive with Incomplete Penetrance

Research Citation(s):

Associated Breed(s):

American Bulldog , American Bully , American Pit Bull Terrier, American Staffordshire Terrier, Australian Bulldog, Boston Terrier, British Bulldog, Bull Arab, Bull Terrier, Bullmastiff, French Bulldog, Southern Cross Bulldog, Staffordshire Bull Terrier ,