Hereditary nasal parakeratosis (HNPK)


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Hereditary Nasal Parakeratosis(HNPK)


Hereditary nasal parakeratosis (HNPK) is an inherited autosomal recessive disorder in Labrador Retrievers. A mutation T>G in the SUV39H2 gene causes the nose to dry out leading to chronic irritation and inflammation of the noses skin.


Symptoms of the disorder generally appear around 6 to 12 months of age. Affected dogs develop dry, rough; gray to brown crusts on the surface and edge of the nose. In some cases, painful cracks around and on the tip of the nose develop and if not treated develop superficial bacterial infections. Over time, the nose often begins to depigment changing skin color from dark to light in color. Although the disorder is nonlife threatening, continuous care to reduce the recurrence of excessive nasal crusting is required throughout the life of the dog.


Because HNPK is a recessive disorder, a dog must have two copies of the mutation in order for the disease to manifest. This means that a dog can have one copy of the mutation and not experience any signs or symptoms of HNPK; this dog would be known as a carrier. The carrier can then pass on either the normal gene or the mutated gene to any offspring. If two carriers are bred, there is a 25% chance of having a dog that receives two mutated copies of the gene and would be affected by HNPK.

Sample Type:

Animal Genetics accepts buccal swab, blood, and dewclaw samples for testing. Sample collection kits are available and can be ordered at test now.

Test Is Relevant To The Following Breeds:

Labrador Retriever


Animal Genetics offers DNA testing for Hereditary Nasal Parakeratosis(HNPK). The genetic test verifies the presence of the recessive mutation T>G in the SUV39H2 gene and presents results as one of the following:

HNPK/HNPK Affected The dog carries two copies of the mutant SUV39H2 gene and is homozygous for HNPK. This dog will be affected and will always pass on the defective gene to it's offspring.
HNPK/n Carrier Both the normal and mutant copies of the gene detected. Dog is a carrier for the SUV39H2 mutation and can pass on a copy of the defective gene to its offspring 50% of the time.
n/n Clear Dog tested negative for the SUV39H2 gene mutation and will not pass on the defective gene to its offspring.