Primary ciliary dyskinesia / PCD (CCDC39-related) - Old English Sheepdog

What does this test examine?

This genetic test analyses the CCDC39 c.286C>T variant for primary ciliary dyskinesia in the Old English Sheepdog. The condition is also known as PCD, primary ciliary dyskinesia, hereditary ciliary dysfunction, and historically as immotile cilia syndrome. When organ laterality is reversed, the term Kartagener syndrome may also be used.

PCD affects motile cilia. These microscopic structures normally help clear mucus, dust and infectious material from the airways and also play a role in reproduction. When cilia do not move properly, mucus clearance is impaired and dogs can develop recurrent respiratory signs, nasal discharge, coughing, bronchopneumonia and reduced fertility. In the Old English Sheepdog, signs are often seen in the first days or weeks of life, and situs inversus can be part of the PCD presentation.

Practical value of this test

• Breeding selection: the test shows whether a dog is clear, carrier or genetically affected for the tested PCD variant.
• Planning matings: breeders can avoid carrier-to-carrier combinations and strongly reduce the risk of affected puppies.
• Early clarity: in a breed with a known variant, DNA testing establishes hereditary status before clinical signs are expected.
• Targeted follow-up: an affected genotype helps owners and veterinarians act faster when respiratory signs, fertility questions or recurrent infections in young pups occur.

Inheritance and result

The trait is inherited as autosomal recessive. A dog with two normal alleles is clear for the tested variant. A carrier has one normal copy and one variant copy and usually does not develop PCD from this variant, but can pass it on. A dog with two copies of the variant has the genotype that causes this breed-specific form of PCD.