Primary Ciliary Dyskinesia

Primary ciliary dyskinesia (PCD) is a congenital canine disease that affects the hair cells of some tissues causing their cilia to be rigid and non-moving or deformed. This is why it is also known as immotile cilia syndrome. Hair cells perform several functions, including the movement of mucus and other substances through the airways.

Symptoms

In dogs with CPD, the cilia of the cells lining the respiratory system do not function properly, resulting in difficulties in removing bacteria and other particles from the airways, thereby increasing the risk of respiratory infections such as bronchitis and pneumonia. Respiratory problems usually appear within a few days of the puppy's birth. Other symptoms include frequent sneezing and runny nose. The disease also affects the sperm cilia, making affected males sterile.

Disease Management

Currently, there is no cure for CPD, and treatment focuses on symptom management and prevention of respiratory infections. With proper infection control, affected dogs can live for several years.

Genetic basis

This disease follows an autosomal recessive mode of inheritance. Autosomal recessive inheritance means that the dog, regardless of sex, must receive two copies of the mutation or pathogenic variant to be at risk of developing the disease. Both parents of an affected dog must carry at least one copy of the mutation. Animals with only one copy of the mutation are not at increased risk of developing the disease, but may pass the mutation on to future generations. Breeding between dogs carrying genetic variants that can cause disease, even if they do not show symptoms, is not recommended.

Technical report

Primary ciliary dyskinesia may be caused by alteration in the CCDC39 and NME5 genes. Here we analyze the c.286C>T mutation of the CCDC39 gene which codes for a protein that has an essential role in cilia structure assembly and motility. The c.286C>T variant was identified in dogs of the Old English Shepherd Dog breed and generates a premature stop codon and an afunctional CCDC39 protein.

Most affected breeds

Old English Sheepdog

Bibliography

Merveille AC, Davis EE, Becker-Heck A,et al. CCDC39 is required for assembly of inner dynein arms and the dynein regulatory complex and for normal ciliary motility in humans and dogs. Nat Genet. 2011 Jan;43(1):72-8.