Hereditary Nasal Parakeratosis (HNPK) in Labradors: What Breeders Need to Know

Hereditary Nasal Parakeratosis (HNPK) is an inherited skin disorder affecting Labrador Retrievers that causes painful, crusty, and fissured skin on the nasal planum (the surface of the nose). While not life-threatening, HNPK significantly affects quality of life — the condition is chronic, progressive, and requires ongoing management. DNA testing allows breeders to identify carriers and prevent producing affected puppies.

What Is HNPK?

HNPK is caused by a mutation in the SUV39H2 gene. The mutation disrupts normal skin cell turnover on the nose, causing keratinocytes (skin cells) to accumulate abnormally. The result is:

• Grey-brown, dry, crusty buildup on the nose surface
• Fissures (cracks) in the nasal skin
• Secondary bacterial infections
• Pain and discomfort, particularly in cold or dry weather
• Occasional nosebleeds from cracking

Signs typically appear at 6–12 months of age and worsen over time. The nose never resolves without treatment. Management involves regular moisturising with products like Vitamin E oil or shea butter and addressing secondary infections.

DNA Testing Results

HNPK is autosomal recessive:

HNPK Clear (N/N): Two normal copies — will not develop HNPK and cannot pass the mutation to offspring

HNPK Carrier (N/HNPK): One normal, one mutant — clinically normal nose, but can pass the mutation. Carrier x carrier pairings produce 25% affected puppies.

HNPK Affected (HNPK/HNPK): Will develop the nasal disease. This dog should not be used for breeding.

Prevalence and Testing Labs

HNPK is found primarily in Labrador Retrievers, with carrier frequency estimated at around 15–20% in some populations. Testing is available from PawPrint Genetics, Laboklin, and Embark (as part of breed-specific health panels). OFA publishes HNPK results when submitted.

Breeding Recommendations

Never breed two carriers together. Carrier x clear pairings produce no affected offspring. As with other recessive conditions, the long-term goal is reducing carrier frequency through selective breeding toward clear dogs without eliminating valuable bloodlines unnecessarily.