Spinal Dysraphism

Other Names: SD
Affected Genes: NKX2-8
Inheritance: Autosomal Recessive
Mutation: chr8:15149895 (canFam3): C>T; chr8:15149895-15149896 (canFam3): 1 bp insertion (ins T)

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Common Symptoms

Spinal dysraphism is an inherited developmental disease affecting weimaraners. Affected dogs have abnormal development of the spinal cord resulting in neurologic disease. Clinical signs range from mild to severe depending upon the severity and location of spinal cord defects. Affected dogs typically present at 4 to 6 weeks of age with a “bunny hopping” gait, a crouching, wide-based stance, and abnormal reflexes in the hind limbs. Abnormal hair growth along the back, curvature of the spine, malformed sternum and kinked tails have also been reported. Clinical signs of the disease do not progress in severity with age.

Breed-Specific Information for the Weimaraner

The Mutation of the NKX2-8 gene associated with spinal dysraphism has been identified in weimaraners. Though the exact frequency in the overall weimaraner population is unknown, approximately 3% out of 109 unrelated weimaraners tested were carriers of the mutation.

Testing Tips

Genetic testing of the NKX2-8 gene in weimaraners will reliably determine whether a dog is a genetic Carrier of spinal dysraphism (weimaraner type). Spinal dysraphism is inherited in an Autosomal Recessive manner in dogs meaning that they must receive two copies of the mutated gene (one from each parent) to develop the disease. In general, carrier dogs do not have features of the disease but when bred with another carrier of the same Mutation, there is a risk of having affected pups. Each pup that is born to this pairing has a 25% chance of inheriting the disease and a 50% chance of inheriting one copy and being a carrier of the NKX2-8 gene mutation. Reliable genetic testing is important for determining breeding practices. In order to eliminate this mutation from breeding lines and to avoid the potential of producing affected pups, breeding of known carriers to each other is not recommended. Weimaraners that are not carriers of the mutation have no increased risk of having affected pups.

There may be other causes of this condition in dogs and a normal result does not exclude a different mutation in this gene or any other gene that may result in a similar genetic disease or trait.

References

  • Confer AW, Ward BC. Spinal dysraphism: a congenital myelodysplasia in the Weimaraner. J Am Vet Med Assoc. 1972 May 15;160(10):1423-6. [PubMed: 5023160]
  • McGrath JT. Spinal dysraphism in the dog. With comments on syringomyelia. Pathol Vet. 1965;2:Suppl:1-36. [PubMed: 5893238]
  • Safra N, Bassuk AG, Ferguson PJ, Aguilar M, Coulson RL, Thomas N, Hitchens PL, Dickinson PJ, Vernau KM, Wolf ZT, Bannasch DL. Genome-Wide association mapping in dogs enables identification of the homeobox gene, NKX2-8, as a genetic component of neural tube defects in humans. PLoS Genet. 2013;9(7):e1003646. [PubMed: 23874236]