Dominant Blue Eyes (DBE)

Dominant Blue Eyes (DBE)

Dominant Blue Eyes (DBE) in Cats — What Breeders and Owners Should Know

Dominant Blue Eyes (DBE) is a newly characterized eye/coat pattern in cats where a cat can have one or two blue eyes (or sectoral heterochromia) along with minimal or very subtle white spotting. The trait segregates as autosomal dominant across multiple founder lines (Altai, Topaz, Celestial, and others). [Dominant B…es_Article | Word]

Introduction

About this research
This page summarizes a peer‑reviewed, open‑access study on Dominant Blue Eyes (DBE) in domestic cats, focusing on newly discovered PAX3 variants that explain blue or odd eyes with minimal white spotting across several founder lines (Altai, Seymour/British, Celestial, Topaz, and others). The authors identified three distinct PAX3 variants—including a newly described RD‑114 LTR insertion (proposed DBEALT allele)—and reviewed their distribution across 14 breeding lineages, confirming that DBE is autosomal dominant yet genetically heterogeneous. [Dominant B…es_Article | Word]

Who conducted the study
The work was led by Dr. Marie Abitbol with collaborators Caroline Dufaure de Citres, Gabriela Rudd Garces, Gesine Lühken, Leslie A. Lyons, and Vincent Gache—researchers known for feline genetics, population genomics, and veterinary medicine. The article is openly available (PMCID PMC11240321, PMID 38997957) and includes links to supplementary material, genotyping datasets (OSF), and accessioned sequences (GenBank/SRA) so breeders and owners can verify details. [Dominant B…es_Article | Word]

Read the full paper

Key takeaways (quick facts)

  • DBE ≠ classic white‑spotting (wS) or dominant white (W): DBE involves distinct genetic changes in the PAX3 gene region, not the KIT locus known for wS/W. [Dominant B…es_Article | Word]
  • At least three PAX3 variants are now associated with DBE across lines:
    1. a PAX3:c.937C>T nonsense variant (Dutch Maine Coon line),
    2. a FERV1 LTR insertion in PAX3 intron 4 (Celestial line and some others),
    3. a newly identified RD‑114 LTR insertion in PAX3 intron 4 (Altai, Seymour British lines, etc.). [Dominant B…es_Article | Word]
  • Health: Risk of deafness varies by variant and genotype. Non‑coding insertions in single copy are generally not linked to deafness, but homozygous (two copies) or compound heterozygous combinations can be associated with bilateral deafness. The Dutch PAX3 nonsense variant shows hearing loss in heterozygotes. Always use BAER where possible. [Dominant B…es_Article | Word]
  • Breeding caution: Avoid DBE × DBE matings between different DBE lines (e.g., Roxi‑derived and Seymour‑derived) due to increased risk of white/deaf or malformed neonates; some pairings have produced white kittens with cranio‑limb abnormalitiesthat died at birth. [Dominant B…es_Article | Word]

What the new study showed

  1. New Altai (DBEALT) variant
    Researchers discovered a new RD‑114 LTR insertion in the 4th intron of PAX3 (accession: NC_018730.3:g.206975776_206975777insN[433]). It’s strongly associated with DBE in Altai and several Seymour‑derived British/Persian/Ragdoll lines. The team proposes this is the DBEALT allele (Altai Dominant Blue Eye). [Dominant B…es_Article | Word]
  2. Previously reported variants
  • DBECEL: a FERV1 LTR insertion in PAX3 intron 4, identified in Celestial and present in some Maine Coon (Topaz‑founded) and Siberian lines; not associated with deafness in Celestials tested by BAER. [Dominant B…es_Article | Word]
  • DBERE: PAX3:c.937C>T nonsense variant (Dutch Maine Coon “Rociri Elvis” line) — hearing loss confirmed (BAER) in heterozygotes; no homozygotes reported (likely lethal). [Dominant B…es_Article | Word]
  1. Genetic heterogeneity
    Of 14 DBE lineages examined, four had no known PAX3 variant, confirming DBE is genetically diverse. Work is ongoing to identify additional variants. [Dominant B…es_Article | Word]

Practical guidance for breeders

Do

  • Test your breeding cats for known PAX3 DBE variants (DBEALT, DBECEL, DBERE) to inform pairings and reduce risk. (Share this paper and its variant IDs with your genetics lab.) [Dominant B…es_Article | Word]
  • Use BAER testing for kittens with blue/odd eyes or with significant white (especially from DBE × DBE or cross‑line matings). [Dominant B…es_Article | Word]
  • Keep thorough pedigree and phenotype records (eye color, white spotting pattern, BAER results) to help map variant flow in your cattery. [Dominant B…es_Article | Word]

Avoid

  • DBE × DBE across different DBE lines (e.g., Roxi lineage × Seymour/Altai lineage). Such matings have produced white, deaf or malformed neonates (e.g., cleft palate, limb contractures). [Dominant B…es_Article | Word]
  • Assuming all blue eyes/white spotting are the same genetic mechanism; DBE is not wS/W. [Dominant B…es_Article | Word]

For kitten buyers

  • Blue or odd eyes can be a benign, beautiful trait — but ask your breeder whether the parents were DNA‑tested for PAX3 DBE variants and whether the litter had BAER hearing tests. [Dominant B…es_Article | Word]
  • A responsible cattery will avoid risky DBE pairings and be transparent about health screening. [Dominant B…es_Article | Word]

FAQ

Q: Is DBE the same as “white spotting (wS)” or “dominant white (W)”?
A: No. wS/W are driven by retroviral changes at KIT; DBE involves PAX3 (different gene, different mechanism). [Dominant B…es_Article | Word]

Q: Can DBE cause deafness?
A: It depends on the variant and zygosity. The Dutch PAX3 nonsense variant shows deafness in heterozygotes; non‑coding LTR insertions are not linked to deafness in single copy, but two DBE alleles (homozygous/compound) can associate with bilateral deafness. Always confirm with BAER. [Dominant B…es_Article | Word]

Q: Are “latent” DBE cats real?
A: Yes—some cats carry a DBE allele but don’t show blue eyes; they may show minimal white or a “red eye” reflex in infancy only. [Dominant B…es_Article | Word]

Q: What is “red-eye” reflex?

A: The “red‑eye reflex” is a normal optical effect seen when light reflects off the blood‑rich retina at the back of the eye.

In simple terms

When a bright light (camera flash, flashlight, ophthalmoscope) hits the eye, it passes through the pupil and reflects back from the retina.
Because the retina is full of blood vessels, the reflection looks red.

Why it matters in DBE kittens

In the DBE research, the authors used “red‑eye reflex” to help identify latent DBE cats:

  • Latent DBE cats carry a DBE‑related PAX3 variant
  • …but they do not show blue eyes as adults
  • As kittens, however, they may show a bright red‑eye flash in photos
    (stronger, more intense than in normal‑pigmented kittens)

This happens because the eye has reduced pigment in early development → letting more light pass through → stronger red reflection.

Key differences

Eye typeRed‑eye reflexMeaning
Normal pigmented eyeMild/typical red flash in photosNormal
Blue or hypopigmented eyeStronger red flashLess pigment, common in blue‑eyed breeds
“Latent DBE” kittenStrong red reflex even without blue eyesSuggests DBE allele with minimal visible effects

Why breeders notice it

It’s a non-invasive early sign that a kitten might carry DBE even if its eyes later turn amber, copper, green, or gold.

Important

It is simply a marker of reduced pigment, common in DBE development.

Red‑eye reflex is not harmful.

It is not the same as the “red glow” associated with eye diseases (like retinal issues).

DBE in British Golden Cats – What Breeders Must Know

Screenshot

British Golden cats (BSH/BLH in golden shaded/shell/golden tabby variations) appear twice in the study:

  • Seymour‑based British line
  • Nanotigr British line
  • Igor British line
  • Nadeya British line
    All four are DBE‑bearing lines with different levels of risk and different underlying mutations.

Below is a clear breakdown specifically for British Golden breeders.

1. The British Golden Breed Hosts 4 Different DBE Lineages

The study includes British SH/LH cats from the following DBE lines:

A) Seymour Line (British Golden included)

  • Founder: Seymour, outbred Russia.
  • Known DBE variant: DBEALT (RD‑114 LTR insertion in PAX3 intron 4).
    [Dominant B…es_Article | Word]
  • British cats from this line all tested heterozygous for DBEALT (never homozygous).

B) Nanotigr Line (British Golden included)

C) Igor Line (British Golden included)

  • Founder: Igor, found in Kazakhstan.
  • None of the three known PAX3 variants present.

    → This means Igor-line British Goldens carry an unknown DBE mutation (a possible 4th mutation). [Dominant B…es_Article | Word]

Several deaf kittens (3 confirmed) have been born in this line.
[Dominant B…es_Article | Word]

D) Nadeya Line (British Golden included)

2. Summary of DBE Risk for British Golden Breeding

For British Golden breeders, the DBE risk depends entirely on which DBE lineage the cat descends from.

Below is a practical overview:

A) If your British Golden cat is from Seymour or Nanotigr (DBEALT)

  • Genotype is typically DBEALT/+.
  • Safe with non‑DBE Golden mates.
  • Risky: DBE × DBE matings (White/deaf kittens possible).
  • VERY DANGEROUS: Crossing Seymour/Nanotigr (DBEALT) with Celestial (DBECEL).

B) If your British Golden cat comes from the Igor line

  • This is a genetically unknown DBE variant (PAX3-negative for known alleles).
  • Deaf kittens have been born even from DBE × non‑DBE.
    [Dominant B…es_Article | Word]
  • Until the mutation is discovered:
    • ALWAYS BAER-test kittens.
    • Avoid Igor × Igor.
    • Avoid Igor × any DBE line (ALT, CEL, Dutch).

C) If your British Golden cat comes from the Nadeya line

  • Also no match to any known PAX3 variant.
  • Behaves like a spontaneous new mutation.
  • Deaf kittens reported.
    [Dominant B…es_Article | Word]
  • Breeding recommendations same as Igor:
    • BAER test
    • Avoid DBE × DBE
    • Avoid mixing Nadeya with any other DBE line

3. The Biggest Danger for British Golden Breeders

Mixing different DBE lines

DBE is not one gene—it’s multiple separate mutations.
When two different DBE alleles combine, results can be severe:

Confirmed in the study:

4. Which DBE Lines Are Unsafe for British Golden Cats?

Unsafe to Mix With British Golden DBE?ReasonCitation
Celestial (DBECEL)Lethal defects with DBEALT; unknown effects with Igor/Nadeya[Dominant B…es_Article | Word]
Altai (DBEALT)Risk of white/deaf homozygotes[Dominant B…es_Article | Word]
Seymour/Nanotigr (DBEALT)Same as above[Dominant B…es_Article | Word]
Dutch Maine Coon (DBERE)PAX3 nonsense mutation; deafness in heterozygotes[Dominant B…es_Article | Word]
Igor/Nadeya (unknown DBE)Completely uncharacterized variants; deafness present[Dominant B…es_Article | Word]

Conclusion:
NEVER mix DBE Golden British with any other DBE line unless genetically tested.

5. Safe Breeding Strategy for British Golden Lines

✔ BEST PRACTICE: DBE × non‑DBE only

  • Choose a healthy, well-pigmented Golden mate (green eyes preferred).
  • No white spotting (WS negative).
  • No DBE background.

✔ Always BAER-test kittens if:

  • they show blue/odd eyes
  • they show red‑eye reflex more intense than usual
  • the DBE line version is unknown (Igor/Nadeya)

✔ DNA testing

Request PAX3 variant testing for:

  • DBEALT (insN[433])
  • DBECEL (insN[395])
  • DBERE (c.937C>T)

If all negative → likely Igor/Nadeya-type unknown mutation.

6. Key Points British Golden Breeders Should Tell Clients

  • Blue/odd eyes in British Goldens are not a safe cosmetic trait — they reflect a dominant mutation.
  • Some DBE variants carry risk of deafness or developmental abnormalities in certain pairings.
  • Ethical breeders avoid DBE × DBE matings.
  • Responsible breeders BAER-test and DNA-test their lines.

Cite the research

  • Open‑access article (full text):
    “Different Founding Effects Underlie Dominant Blue Eyes (DBE) in the Domestic Cat” — with figures, lineage tables, and methods.
    Read the paper
  • Supplementary materials (figures, primer tables, variant details):
    MDPI Supplementary ZIP (7.9 MB)
  • Public datasets and accessions:
    OSF SNP dataset: https://osf.io/k798c/
    GenBank (PAX3 intron 4 sequence): PP332291 (link in the paper) 
    SRA (whole‑genome sequence): PRJNA1073398, SAMN39921596 (links in the paper) [Dominant B…es_Article | Word]
  • Background reading for breed histories & DBE lines:
    Messybeast overview pages (Altai, Topaz, Maine Coon DBE, blue‑eye breeds) — links embedded in the paper’s figure legends and discussion. [Dominant B…es_Article | Word]