Acute Respiratory Distress Syndrome in Dalmatians - ARDS

Acute respiratory distress syndrome (ARDS) is an inherited uncurable lung development disorder that affects young dogs (4 - 10 months) and result in death or euthanasia of the affected dog. The main clinical symptoms include difficult breathing (rapid, noisy breathing, coughing, stretched neck – breathing with the help of abdominal muscles), blue discoloration of mucosa (non-oxidation of tissues/cyanosis) and pneumonia. This is due to the reduced exchange of respiratory gases in the pulmonary tissue resulting in acute respiratory distress. Besides the respiratory problems the dead puppies had renal aplasia and increased amount of cerebrospinal fluid (CSF) in brain cavities – brain edema. ARDS occurs in both humans and dogs.

The familial lung disease is caused by a mutation in the ANLN gene. This gene encodes the anillin- actin binding protein that is expressed mainly in lungs. This protein plays an important role in organisation of epithelial cells in bronchial tubes and air sacks that are necessary for the transfer of the respiratory gases between lungs and the blood. The mutation causes the production of truncated protein, which abolishes the protein function and thus causes disorganisation in cell assembly and cell junction and disturbed epithelial regeneration and results in pulmonary complications.

The mutation that causes the ARDS is inherited autosomal recessively. The disease develops only in individuals that inherited the mutated gene from both parents. These individuals are designated as P/P (positive/positive). The carriers of the mutated gene referred to as N/P (negative/positive) have only one mutated gene from one parent and show no clinical symptoms. However, they pass on this disease to their offspring. Genetic testing can detect the presence of the mutated allele and prevent further spreading of this disease.

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Reference:

Holopainen, S., Hytönen, M. K., Syrjä, P., Arumilli, M., Järvinen, A. K., Rajamäki, M., & Lohi, H. (2017). ANLN truncation causes a familial fatal acute respiratory distress syndrome in Dalmatian dogs. PLoS genetics, 13(2), e1006625.