Canine Mendelian disease record

Hereditary Nasal Parakeratosis (Discovered in the Labrador Retriever; HNPK)

Q: How well studied is Hereditary Nasal Parakeratosis (Discovered in the Labrador Retriever; HNPK) in dogs?

OMIA curates 7 peer-reviewed references for Hereditary Nasal Parakeratosis (Discovered in the Labrador Retriever; HNPK). The full, linked citation list is on this page.

Hereditary Nasal Parakeratosis (Discovered in the Labrador Retriever; HNPK). Autosomal recessive. Observed in 6 of 266 breeds tested in the Sniff Atlas, with measured carrier frequencies drawn from 242,665 dogs (Donner 2023). Per-dog phenotype outcome depends on penetrance, modifiers, and environment; the carrier frequencies below describe variant prevalence, not disease incidence.

OMIA identifier: OMIA:001373-9615
Inheritance: Autosomal recessive
Source dataset: Sniff Atlas v1.0.1 / DOI

About this disease

From OMIA's curated record

Documented in OMIA (Online Mendelian Inheritance in Animals). This describes the disease as recorded in the published literature, not a prediction for any individual dog. As of 2026-06-03.

Clinical features

As summarised by Jagannathan et al. (2013), "HNPK affected dogs develop crusts and fissuring of the nasal planum at a young age but are otherwise healthy. The pathognomonic histopathological changes consist of a marked diffuse parakeratotic hyperkeratosis characterized by the retention of nuclei in the stratum corneum and an accumulation of proteinaceous fluid (“serum lakes”) within the stratum corneum".

Molecular genetics

Whole-genome sequencing of one of the affected dogs by Jagannathan et al. (2013), and comparison of this sequence in the ~1.6Mb candidate region with the canine reference sequence revealed four non-synonymous variants, one of which "turned out to represent an artifact due to an error in the reference genome assembly". Genotyping of the other three variants in a large (>500) cohort of affected and control dogs identifed the causal mutation as c.972T>G in the SUV39H2 gene "encoding the “suppressor of variegation 3-9 homolog 2 (Drosophila)”, a histone 3 lysine 9 (H3K9) methyltransferase". "The variant results in the change of an asparagine residue in the catalytically active SET domain to a lysine (p.N324K). The SET domain has been named according to the first proteins, in which it has been identified, Suvar(3)9, enhancer of zeste, and trithorax. SIFT and Polyphen-2 predict that the p.N324K variant affects protein function . . . . The asparagine at position 324 is highly conserved across all known SUV39H2 orthologs and even across many other related H3K9 methyltransferases". The same authors also comment that "A loss of SUV39H2 function is predicted to result in delayed differentiation, which is compatible with the histopathological changes that we observed in biopsies from nasal epidermis of HNPK affected Labrador Retrievers." Bauer et al. (2018): "Whole genome sequencing of one affected Greyhound revealed a 4-bp deletion at the 5′-end of intron 4 of the SUV39H2 gene that was absent in 188 control dog and three wolf genomes. The variant was predicted to disrupt the 5′-splice site with subsequent loss of SUV39H2 function. The six affected puppies were homozygous for the variant, whereas the two non-affected littermates were heterozygous."

Inheritance

Page et al. (2003) reported evidence consistent with autosomal recessive inheritance.

Human analog

OMIA links this condition to the human gene record in OMIM (Mendelian Inheritance in Man), the place to read across to the deeper human literature for the same biology.

Gene · OMIM 606503

Source: OMIA (Nicholas, Tammen & the Sydney Informatics Hub), entry OMIA:001373-9615, doi:10.25910/2AMR-PV70 (CC-BY 4.0).

The evidence

Published references

The peer-reviewed papers behind this disease, curated by OMIA. Starred entries are OMIA-designated landmark papers. Showing 6 of 7.

Genome sequencing of 2000 canids by the Dog10K consortium advances the understanding of demography, genome function and architecture. · Genome Biol · 2023 · PMID 37582787
Genetics of inherited skin disorders in dogs. · Vet J · 2022 · PMID 34861369
Abnormal keratinocyte differentiation in the nasal planum of Labrador Retrievers with hereditary nasal parakeratosis (HNPK). · PLoS One · 2020 · PMID 32119674
A splice site variant in the SUV39H2 gene in Greyhounds with nasal parakeratosis. · Anim Genet · 2018 · PMID 29423952
A mutation in the SUV39H2 gene in Labrador Retrievers with hereditary nasal parakeratosis (HNPK) provides insights into the epigenetics of keratinocyte differentiation. · PLoS Genet · 2013 · PMID 24098150
Hereditary nasal parakeratosis in Labrador Retrievers · Veterinary Dermatology · 2003 · PMID 12662268

References curated by OMIA (Nicholas, Tammen & the Sydney Informatics Hub), doi:10.25910/2AMR-PV70 (CC-BY 4.0). Full list at the OMIA entry.

Predict a litter

Set each parent's status for Hereditary Nasal Parakeratosis (Discovered in the Labrador Retriever; HNPK) and see the odds for their puppies. Single recessive variant, exact Mendelian math.

Parent A

Parent B

NNClear

NmCarrier

mmAffected

Clear25%

Carrier50%

Affected25%

These are the genetic odds for one known variant, not a promise: a real litter varies around them, and penetrance or other genes can change whether the condition ever appears. Use it to avoid pairing two carriers and to keep a line healthy, not to engineer a dog. Inheritance mode per OMIA.

Your breed

See what Hereditary Nasal Parakeratosis (Discovered in the Labrador Retriever; HNPK) looks like in your dog's breed.

Carrier frequency by breed

Top 5 well-sampled breeds (n ≥ 50)

Maximum carrier frequency per breed across variants in the Donner 2023 cohort, with Wilson 95% confidence intervals. The list below is split into well-sampled breeds (n ≥ 50 tested) and small-sample breeds (n < 50, where the Wilson CI typically spans more than 20 percentage points and frequencies should not be compared directly to the well-sampled entries). Frequencies are population-level, not per-litter or per-line.

0%5%10%

Greyhound3.8% · n 105

3.8%n 105

Labrador Retriever2.0% · n 16,856

2.0%n 16,856

Australian Cattle Dog<0.1% · n 982

<0.1%n 982

German Shepherd<0.1% · n 15,648

<0.1%n 15,648

American Staffordshire Terrier<0.1% · n 42,793

<0.1%n 42,793

n = 76,384 dogs · Donner et al. 2023 carrier-screening cohort · Sniff Atlas

Each bar is one well-sampled breed; the whisker is its Wilson 95% CI, and fainter bars have wider intervals. Frequencies are population-level, not per-litter. Carrier status for Hereditary Nasal Parakeratosis (Discovered in the Labrador Retriever; HNPK) is measured; phenotype outcome depends on penetrance and modifiers.

▸ Full table with Wilson 95% confidence intervals

Breed	Carrier frequency	Wilson 95% CI	n tested
Greyhound	3.8%	[1.5%, 9.4%]	105
Labrador Retriever	2.0%	[1.8%, 2.2%]	16,856
Australian Cattle Dog	<0.1%	[0.0%, 0.5%]	982
German Shepherd	<0.1%	[0.0%, 0.0%]	15,648
American Staffordshire Terrier	<0.1%	[0.0%, 0.0%]	42,793

▸ Also observed in 1 small-sample breed (n < 50)

Frequencies in this section are statistical estimates with wide Wilson 95% confidence intervals (typically >20 percentage points). Treat these as "carriers observed but the true population frequency is not yet measurable" rather than as comparable to the well-sampled entries above.

Breed	Estimate	Wilson 95% CI	n tested
Saluki	4.2%	[0.7%, 20.2%]	24

260 additional breeds in the Donner 2023 cohort were tested but showed no carriers.

Penetrance

From genotype to phenotype

Carrier status is not the same as disease status. Penetrance is the fraction of at-risk dogs that develop the phenotype. The Donner 2023 S4 table tracks this for 1 variant(s) underlying this disease in the cohort.

At-risk dogs evaluated: 1
Phenotype confirmed: 0
Penetrance range: not yet quantifiable

Predicted disease relevance at the per-dog level is UNPROVEN. The carrier frequency is measured; phenotype outcome is governed by penetrance, environment, and modifier loci. Consult a veterinarian for clinical interpretation.

How to cite this record

If you use this record in published work, cite the Sniff Atlas (the published dataset that carries the breed-level carrier frequencies) and the upstream sources:

Sniff Atlas v1.0.1 for the per-breed carrier frequencies:
Gehring, M. (2026). Sniff Atlas v1.0.1. Zenodo. https://doi.org/10.5281/zenodo.20566358. CC-BY 4.0.
OMIA for the disease definition, inheritance, and gene assignment:
Nicholas, F. W., & Tammen, I. (2024). OMIA. Sydney Informatics Hub, The University of Sydney. https://doi.org/10.25910/2AMR-PV70. Entry: OMIA:001373-9615.
Donner et al. 2023 for the breed × variant carrier-frequency cohort:
Donner, J., Freyer, J., Davison, S., Anderson, H., Blades, M., Honkanen, L., et al. (2023). Genetic prevalence and clinical relevance of canine Mendelian disease variants in over one million dogs. PLOS Genetics, 19(2), e1010651. https://doi.org/10.1371/journal.pgen.1010651.

Full citation formats (BibTeX, RIS, CITATION.cff) at sniff.world/cite.

Sniff Atlas v1.0.1, the source dataset for these frequencies.
Browse breeds, per-breed Mendelian profiles, including this disease in context.
OMIA entry OMIA:001373-9615, authoritative clinical reference.
About OMIA, the catalogue this record comes from, and how Sniff uses it.

Last updated June 20, 2026

Sources: Sniff Atlas v1.0.1 · OMIA OMIA:001373-9615 · Donner et al. 2023