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Canine Mendelian disease record

Progressive Retinal Atrophy (Discovered in the Lapponian Herder; IFT122-PRA)

Progressive Retinal Atrophy (Discovered in the Lapponian Herder; IFT122-PRA). Autosomal recessive. Observed in 3 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:002320-9615
Autosomal recessive
Source dataset
Sniff Atlas v1.0.1 / DOI
The human connection

A model of human cranioectodermal dysplasia 1

This is the canine counterpart of cranioectodermal dysplasia 1 in people. That makes affected dogs a naturally-occurring model of the human disease, and it is part of why studying dogs moves medicine forward for everyone. It does not mean your dog has the human disease. It means the two share an underlying biology.

In people, the disease is described as: Any cranioectodermal dysplasia in which the cause of the disease is a mutation in the IFT122 gene.

In humans it is also called: CED1, cranioectodermal dysplasia type 1, IFT122 cranioectodermal dysplasia.

MONDO:0021093 OMIM 218330

Mapped from OMIA via the human disease's OMIM entry to the Mondo Disease Ontology (Monarch Initiative, CC-BY 4.0). Sniff renders this as a model-of link; the canine disease remains the subject of this page.

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.

Summary

Kaukonen et al. (2021): "Retinitis pigmentosa (RP) is a blinding eye disease affecting nearly two million people worldwide. Dogs are affected with a similar illness termed progressive retinal atrophy (PRA). Lapponian herders (LHs) are affected with several types of inherited retinal dystrophies, and variants in PRCD and BEST1 genes have been associated with generalized PRA and canine multifocal retinopathy 3 (cmr3), respectively. However, all retinal dystrophy cases in LHs are not explained by these variants ... . We report here a recessive missense variant in IFT122 as a candidate causal variant for a novel canine RP model ... ."

Clinical features

Kaukonen et al. (2021): "examinations had revealed clinical findings compatible with generalized PRA in 10 LHs (five males, five females), as these dogs presented with bilateral, diffuse tapetal hyperreflectivity and vessel attenuation. Two of the 10 cases were only examined as young or middle-aged adults (at 1.9 and 5.1 years of age) when they exhibited only mild fundus changes and were therefore diagnosed to have “PRA suspected”. The remaining eight dogs were also examined later in life and had been diagnosed as “PRA affected” at an average age of 9.0 years (± SD 2.9). Typical early findings included night blindness and diffuse tapetal hyperreflectivity. Disease progression was slow as some of the affected dogs still had some visual capacity left at 13 years. All the cases were genotyped for the PRCD p.C2Y and the cmr3 (p.P463fs, p.G489V) variants ... . Of the 10 cases, all were wild-type for the PRCD variant, while four were wild-type and six heterozygous for the two cmr3 variants ... . Spectral-domain optical coherence tomography (SD-OCT) was performed ... . The thicknesses of the whole retina with the retinal pigment epithelium (RPE) and outer retinal layers, including outer nuclear layer, inner segments and outer segments of photoreceptors, and RPE, were severely reduced in the affected dog ... . Interestingly, the photoreceptor layer was not completely lost despite the dog’s old age ... . Apart from the ocular signs, all three dogs were clinically healthy."

Molecular genetics

Kaukonen et al. (2021): "whole-genome sequencing of an affected LH [Lapponian Herders] revealed a missense variant, c.3176G>A, in the intraflagellar transport 122 (IFT122) gene. The variant was also found in Finnish Lapphunds, in which its clinical relevancy needs to be studied further. The variant interrupts a highly conserved residue, p.(R1059H)."

Inheritance

Kaukonen et al. (2021): "Pedigree analysis suggested autosomal recessive PRA in LH [Lapponian Herders], as affected dogs were born to unaffected individuals, there were multiple cases in one of the affected litters, and both sexes were equally affected."

Human analog

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

Disease · OMIM 218330 Gene · OMIM 606045

Source: OMIA (Nicholas, Tammen & the Sydney Informatics Hub), entry OMIA:002320-9615, 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.

  2. The Blue Book: Ocular disorders presumed to be inherited in purebred dogs. 13th Edition · https://ofa.org/wp-content/uploads/2022/10/ACVO-Blue-Book-2021.pdf · 2021

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 Progressive Retinal Atrophy (Discovered in the Lapponian Herder; IFT122-PRA) and see the odds for their puppies. Single recessive variant, exact Mendelian math.

Parent A
Parent B
NNClear
NmCarrier
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 Progressive Retinal Atrophy (Discovered in the Lapponian Herder; IFT122-PRA) looks like in your dog's breed.
Carrier frequency by breed

Top 2 well-sampled breeds (n ≥ 50)

Maximum per breed across variants in the Donner 2023 cohort, with . 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%10%20%
Finnish Lapphund2.6% · n 57
American Staffordshire Terrier<0.1% · n 42,793
n = 42,850 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 Progressive Retinal Atrophy (Discovered in the Lapponian Herder; IFT122-PRA) is measured; phenotype outcome depends on penetrance and modifiers.
▸ Full table with Wilson 95% confidence intervals
Breed Carrier frequency n tested
Finnish Lapphund 2.6% 57
American Staffordshire Terrier <0.1% 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 n tested
Lapponian Herder 15.4% 26

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

Scope of this record

Scope

This record carries the breed-level carrier frequencies from the Donner 2023 cohort. Penetrance data (the fraction of at-risk dogs that develop the phenotype) is not yet quantified for this disease in the Sniff Atlas v1.0.1. The OMIA entry is the authoritative reference for the clinical phenotype, inheritance pattern, and gene assignment.

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

How to cite this record

Citations

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:002320-9615.

  • 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.

Related

Related

Last updated
Sources: Sniff Atlas v1.0.1 · OMIA OMIA:002320-9615 · Donner et al. 2023