Hereditary nasal parakeratosis (greyhound type) is an inherited skin disease affecting dogs. Affected dogs present as puppies with dry, rough, gray to brown crusts and rarely, painful cracks on the tip of the nose. The noses of affected dogs are prone to superficial bacterial infections and often become depigmented over time. Affected dogs are otherwise healthy. Symptoms often wax and wane in severity over the dog’s life. Though manageable, this disorder requires continuous topical therapy to prevent recurrence of excessive nasal crusting.
Genetic testing of the SUV39H2 gene will reliably determine whether a dog is a genetic Carrier of hereditary nasal parakeratosis (greyhound type). Hereditary nasal parakeratosis (greyhound type) 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 SUV39H2 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.
Bannoehr J, Balmer P, Stoffel MH, Jagannathan V, Gaschen V, Kühni K, Sayar B, Drögemüller M, Howald D, Wiener DJ, Leeb T, Welle MM, Müller EJ, Roosje PJ. Abnormal keratinocyte differentiation in the nasal planum of Labrador Retrievers with hereditary nasal parakeratosis (HNPK). PLoS One. 2020 Mar 2;15(3):e0225901. doi: 10.1371/journal.pone.0225901.
Bauer A, Nimmo J, Newman R, Brunner M, Welle MM, Jagannathan V, Leeb T. A splice site variant in the SUV39H2 gene in Greyhounds with nasal parakeratosis. Anim Genet. 2018 Apr;49(2):137-140. doi: 10.1111/age.12643.