Pulmonary Surfactant Metabolism Dysfunction in Airedale Terriers

The pulmonary surfactant is essential for proper lung function and oxygen exchange, as it reduces the surface tension in the alveoli and prevents their collapse during breathing. A defect in the processing and release of surfactant leads to impaired lung expansion, alveolar collapse and damage to lung tissue. The lungs are edematous, congested, poorly ventilated and lose normal elasticity. Clinically, the disease manifests itself in newborn puppies, which develop shortness of breath, rapid breathing, weakness and refusal to suckle shortly after birth. The condition worsens rapidly, and most affected puppies die within the first days of life due to respiratory failure.

The cause of the disease is a missense mutation c.1159G>A in the LAMP3 gene, which is involved in surfactant metabolism in lung cells. The mutation is inherited in an autosomal recessive manner. This means that the disease only develops in individuals who inherit the mutated gene from both their parents. Carriers of the mutated gene are clinically healthy, but they pass the mutation on to their offspring. In the case of mating two heterozygous individuals, theoretically 25% of the offspring will be completely healthy, 50% of the offspring will be carriers, and 25% of the offspring will inherit the mutated gene from both parents and will therefore be affected by this disease.

A genetic test can clearly reveal the genotype of the animal and is a suitable tool for breeders to prevent the unintentional breeding of affected puppies.

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References:

Dillard, K.J., Ochs, M., Niskanen, J.E., Arumilli, M., Donner, J., Kyöstilä, K., Hytönen, M.K., Anttila, M., Lohi, H. : Recessive missense LAMP3 variant associated with defect in lamellar body biogenesis and fatal neonatal interstitial lung disease in dogs. PLoS Genet 16:e1008651, 2020. Pubmed reference: 32150563