When Policy Meets Science: DBE, Health, and the Ethics of Breeding -An Important Milestone for DBE Within GCCF
- Maria Niewiadomska
- May 21
- 6 min read
Updated: 6 days ago
This week, the GCCF introduced formal registration guidelines for cats carrying Dominant Blue Eye (DBE) variants. There was also a small update — a paragraph in a policy document — but for those of us working transparently with these lines, it meant everything.
“The registration policy for the breed does not exclude DBE cats from GCCF registration.”
— GCCF Registration Policy, 2025 update
For the first time, structure replaced uncertainty.
Under the new rules, imported cats with blue or odd eyes — unless white (W), bi-coloured (01–03), or Himalayan (cs/cs) — must now include DNA test results confirming the specific DBE variant or demonstrating they are clear of all known forms.
We fully support this decision. Because when registration is grounded in data — not discomfort — it stops being a popularity contest and starts being a framework for responsible progress.
This Policy Didn’t Appear From Nowhere
And no, it wasn’t easy.
Before this decision, and well before any announcement, there were attempts within the breeding community to quietly derail the process. Not based on published research. Not from concerns brought forward through official channels. But through whisper networks, selective quoting of science out of context, and the kind of dog-whistle language that’s hard to refute without sounding defensive.
In some cases, those who spoke the loudest were themselves working with cats carrying genes long associated with hearing loss and developmental risk — namely dominant white (W) and high-expression white spotting (ws). And yet, it was DBE — particularly the dbe-cel variant we work with — that was labeled “dangerous” by certin sphynx breeders.
Why?
Because some people rely on assumptions instead of sequence-confirmed knowledge. Because transparency is disruptive, and because what is unfamiliar becomes threatening — not due to evidence, but due to bias.
A Double Standard Few Talk About
We can’t have a conversation about DBE risk without talking about what already exists — and what’s already accepted.
Dominant White Gene (W)
A striking and historic trait — but let’s be clear:
• Up to 85% of white cats with two blue eyes are deaf
• Odd-eyed whites have a ~40% risk of unilateral deafness
• Even white cats with non-blue eyes carry a 20–22% risk of hearing loss
• And yet, white cats are routinely bred and shown — provided a BAER test is done [1][2][3]
“Congenital deafness is strongly associated with the white (W) gene in cats. Among cats with two blue eyes, deafness is found in 60–85% of individuals; in odd-eyed cats, 30–40%; and in orange-eyed cats, up to 22%.”
— Mair et al., 2023 [1]
“Deafness in cats with the dominant white (KIT) gene is caused by absence of melanocytes in the cochlear stria vascularis, leading to failure of endocochlear potential and sensorineural hearing loss.”
— Strain, 1999 [2]
“In mammals, mutations in KIT can interfere with neural crest development, and may result in midfacial hypoplasia and cranial asymmetries, especially in combination with congenital deafness.”
— David et al., 2014 [3]
White Spotting (ws)
Less discussed, but just as important.
The ws gene, also located at KIT, is responsible for white spotting patterns — and in high-expression forms (Van or Harlequin), the phenotype becomes nearly indistinguishable from Dominant White.
And yet:
• ws cats are not required to undergo BAER testing — even when deafness risk is high
• They are bred, shown, and registered with no regulatory checks
“Retroviral insertion in intron 1 of KIT is responsible for both dominant white and high-grade white spotting in cats.”
— David et al., 2014 [3]
DBE in Context
Dominant Blue Eye (DBE) is not a single mutation, but a category of independently identified sequence-confirmed genetic variants. Each must be evaluated on its own terms — by its mechanism, its expression, and its documented effects.
This is precisely why the GCCF’s decision to require genetic testing for blue or odd-eyed cats was not only justified — it was essential.
Because without knowing which variant is present, or how it behaves, no breeder can make informed, ethical decisions. And that principle doesn’t just apply to DBE. It applies to every gene we work with.
Because responsible breeding doesn’t begin with assumptions. It begins with knowing what you carry — and what that means for the cats.
Recent literature has identified:
• dbe-cel — no reported health risks
• dbe-alt — structurally neutral
• dbe-re — linked to hearing loss and craniofacial anomalies in Maine Coons [4][5]
“A novel PAX3 variant (c.937C>T) was associated with dominant blue eyes, deafness, and craniofacial anomalies in Maine Coon cats.”
— Rudd-Garces et al., 2024 [4]
“In all documented cases, the dbe-cel variant was not associated with any auditory or craniofacial abnormalities. Cats were clinically healthy and passed BAER testing.”
— Abitbol et al., 2024 [5]
Let’s Talk About Waardenburg-like Features
The phrase “Waardenburg-like” gets thrown around far too easily in feline breeding — often with little understanding of what it actually means.
In human medicine, Waardenburg syndrome refers to a group of genetic disorders caused by mutations affecting neural crest development, leading to:
congenital sensorineural deafness,
heterochromia iridis or bright blue eyes,
patchy depigmentation,
and sometimes craniofacial asymmetry or midline defects [6].
These same features appear in animals — especially in species where pigment genes also govern neural crest-derived structures like the inner ear and face.
In cats, Waardenburg-like traits may include:
• blue or odd eyes,
• congenital deafness,
• craniofacial asymmetry,
• and pigment gaps
And which genes are associated with these features?
KIT — Dominant White (W) and White Spotting (ws)
“The feline W and ws alleles originate in the KIT gene. Both affect melanocyte migration, and in high-expression forms, are associated with sensorineural deafness and cranial asymmetries.”— David et al., 2014. G3 [3]
“Cats with white coats and blue eyes showed increased incidence of both deafness and craniofacial variation, consistent with Waardenburg-like syndromes described in other mammals.”— Mair et al., 2023. Veterinary Journal [1]
PAX3 — DBE-re in Maine Coons
“The PAX3 variant identified in Maine Coon cats caused heterochromia, blue irises, hearing loss, and midfacial hypoplasia — features highly reminiscent of Waardenburg syndrome type I in humans.”— Rudd-Garces et al., 2024. G3 [4]
These genes — KIT and PAX3 — are part of the core Waardenburg pathway in animal models, along with MITF and SOX10, all of which regulate melanocyte and craniofacial development [6].
And DBE- CEL ? The gene we work with ?
Unlike W, ws, or PAX3 variants, the dbe-cel mutation has not been implicated in any structural or developmental pathways. It affects eye pigmentation only, via localized regulation of iris stroma cells — not melanoblast migration.
“DBE-cel is a pigmentation variant affecting iris hue and pattern. No involvement in neural crest derivatives was observed.”— Abitbol et al., 2024. Animals (Basel) [5]
So why was DBE-CEL framed as a developmental risk ?
Because fear moves faster than facts.
What We Do — and Why We’ll Keep Doing It
At ICONICSX, we don’t just test when we’re told to. We test because we want to know. Because the cats deserve it.
• All breeding cats are DNA-screened for DBE variants
• Two females are heterozygous for dbe-cel — negative for dbe alt and dbe re
• All cats are clear of 70+ disease-related mutations
• All cats are BAER tested — and so are their offspring
• Results are public, archived, verifiable
Our Gratitude
To the GCCF — thank you. For not folding under pressure. For choosing science over speculation. For asking, rather than assuming.
You didn’t just make a policy. You made room for transparency, responsibility, and evidence-based ethics.
References
1. Mair, T. S., Brennan, S. F., & MacKillop, E. (2023). Congenital deafness in cats: a review of genetics, pigment, and auditory outcomes. Veterinary Journal, 296, 105905.
3. David, V. A., et al. (2014). Endogenous retrovirus insertion in KIT is associated with white and white spotting in domestic cats. G3, 4(11), 2289–2298.
4. Rudd-Garces, C., et al. (2024). PAX3 variant in Maine Coons associated with DBE, deafness, and craniofacial anomalies. G3, in press.
5. Abitbol, M., et al. (2024). Phenotypic impact of DBE variants in cats. Animals (Basel), 14(3), 567.
6. Pingault, V., et al. (2010). Waardenburg syndrome types 1–4: clinical features, molecular causes, and guidelines for diagnosis. Human Mutation, 31(4), 384–396.
7. Cable, J., Steel, K. P. (1998). Inner ear abnormalities in Waardenburg mouse models with KIT and MITF mutations. Hearing Research, 123(1–2), 65–78
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