Spondylocostal Dysostosis

Other Names: Comma defect, SCD
Affected Genes: HES7
Inheritance: Autosomal Recessive
Mutation: chr5:32945846 (canFam3): 1 bp deletion (del G)
Breed(s): Miniature Schnauzer, Schnoodle

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Common Symptoms

Spondylocostal dysostosis is an inherited skeletal disorder affecting dogs. Puppies with this condition are born dead or die shortly after birth. Affected puppies have multiple skeletal abnormalities of the spinal column and ribs and their hindquarters are less developed than their forequarters. These abnormalities cause the spinal column to be shortened and give them a comma-like shape. They may also display other congenital abnormalities such as umbilical hernias and cleft palates.

Testing Tips

Genetic testing of the HES7 gene will reliably determine whether a dog is a genetic Carrier of spondylocostal dysostosis. Spondylocostal dysostosis 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 HES7 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. Dogs 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.


  • Willet CE, Makara M, Reppas G, Tsoukalas G, Malik R, Haase B, Wade CM. Canine disorder mirrors human disease: exonic deletion in HES7 causes autosomal recessive spondylocostal dysostosis in miniature Schnauzer dogs. PLoS One. 2015 Feb 6;10(2):e0117055. [PubMed: 25659135]