Buying a DBE Kitten

Buyer Checklist

1. Ask for the Kitten’s Own DBE Genetic Test

Always ask for the individual kitten’s DBE genetic test result, rather than relying only on the genetic status of its parents.

If one parent carries a heterozygous DBE variant and the other parent is genetically negative, each kitten has approximately a 50% chance of inheriting that variant. This means that parental test results alone cannot confirm the genetic status of an individual kitten.

Every kitten advertised, priced or sold as carrying a known DBE variant should have its own traceable genetic result.

The laboratory report should clearly state:

• the identity or sample reference of the kitten tested;

• which DBE variant(s) were tested;

• which DBE variant was identified, if present;

• whether the kitten is heterozygous, where applicable;

• which laboratory performed the analysis;

• and the date of testing.

Whenever possible, choose breeders who use laboratories that provide independent certificate verification, allowing buyers to confirm the authenticity of the genetic report directly with the testing laboratory.

It is also important to understand which cats were genetically tested. While testing for additional colour-associated variants is generally performed on the breeding cats rather than every kitten, every kitten represented as carrying a DBE variant should have its own individual DBE genetic test.

Why It Matters

Blue eyes, odd eyes and white markings describe phenotype. They do not identify the underlying genotype.

A white, white-spotted, bicolour, harlequin or van kitten with blue or odd eyes may carry:

• a known PAX3-associated DBE variant;

• KIT dominant white;

• KIT-associated white spotting;

• both a PAX3-associated DBE variant and a KIT allele;

• or another, currently unresolved genetic cause.

These possibilities cannot be distinguished reliably from appearance alone.

A kitten should not be represented as carrying a specific known DBE variant unless that claim is supported by its own individual genetic test.

A higher price, premium “DBE” label or visually striking eye colour does not constitute genetic evidence.

2. Check Exactly What Was Tested

A report stating only “DBE positive” is not sufficiently informative.

Ask which specific variants were included in the test panel. Currently characterised PAX3-associated variants include DBE-CEL, DBE-ALT, DBE-RE and DBE-AGO.

A test result applies only to the variants examined by that laboratory. A negative result for the currently characterised variants does not exclude an unresolved genetic cause of blue or odd eyes.

However, a negative result also cannot be used to claim that the kitten carries a specific known DBE variant.

For a kitten intended for breeding, ask for:

• the kitten’s individual DBE results;

• the DBE results of both parents;

• the kitten’s KIT dominant-white and white-spotting status, where relevant;

• the parents’ KIT results;

• and a clear explanation of the mating.

3. Ask Whether DBE and KIT Were Combined

Ask whether either parent carries KIT dominant white or KIT-associated white spotting in addition to a PAX3-associated DBE variant.

KIT dominant white and KIT white spotting are genetically distinct and should not be treated as the same condition.

KIT dominant white has an independently documented association with iris hypopigmentation and an incompletely penetrant risk of deafness. Current evidence does not demonstrate the same hearing-risk association for KIT white spotting alone.

No peer-reviewed study has yet quantified whether combining a PAX3-associated DBE variant with KIT dominant white or KIT white spotting creates an additional or interacting risk of deafness.

This means that an additional risk cannot currently be confirmed or excluded.

For buyers considering a kitten for breeding, a deliberate DBE × KIT combination should be disclosed clearly. Ask the breeder:

• why the mating was chosen;

• which DBE and KIT variants were present in the parents;

• whether every kitten was tested individually;

• whether the kittens underwent BAER testing;

• and how the breeder intends to monitor hearing and long-term health.

Combining DBE with KIT may also make it more difficult to determine which genetic mechanism produced the kitten’s blue eyes, odd eyes or white pattern. This increases the importance of transparent, individual testing.

4. Request the Kitten’s BAER Hearing Test

Request the kitten’s own BAER — Brainstem Auditory Evoked Response — hearing-test report, particularly when the kitten:

• is advertised as DBE;

• has blue or odd eyes;

• is white or extensively white-spotted;

• comes from a lineage associated with hearing impairment;

• results from a DBE × KIT mating;

• or is being purchased for breeding.

BAER testing objectively assesses auditory function and can identify unilateral as well as bilateral hearing impairment.

The report should record the result for the left and right ear separately.

Eye colour, coat pattern, response to household sounds and breeder observation cannot reliably exclude unilateral deafness.

Why It Matters

Hearing outcomes differ among DBE variants and genotypes.

Hearing impairment has been documented in heterozygous DBE-RE cats and in particular compound or homozygous PAX3 genotypes. KIT dominant white also carries an independently documented hearing risk.

A kitten that appears to respond normally to sound may still have unilateral hearing loss. Only an objective hearing assessment can establish the hearing status of each ear.

5. Verify the Genetic and Hearing Reports

Ask to see the original laboratory and BAER reports, rather than screenshots containing only selected results.

Check that the reports contain enough information to connect them to the kitten being offered, such as:

• the kitten’s registered name or identifying details;

• microchip number, where available;

• sample or report reference;

• date of birth;

• date of testing;

• laboratory or veterinary provider;

• and the complete result.

Where a kitten was tested before microchipping, ask how the breeder linked the biological sample to that individual kitten.

Altered photographs, certificates without identifying information and parental reports presented as proof of the kitten’s status should not be accepted as individual confirmation.

6. Do Not Use Flash Photographs to Identify DBE

A red-eye reflection in a photograph is not evidence that a kitten carries a DBE variant.

Reflections in photographs vary according to:

• lighting;

• camera angle;

• pupil size;

• position of the flash;

• and the stage of ocular development.

The same kitten may show different reflections in different photographs. A red, orange or other reflected colour cannot confirm or exclude DBE, predict permanent eye colour or identify a specific variant.

Flash photography is not a validated genetic or diagnostic test.

Do not place a deposit or pay a DBE-related premium solely on the basis of neonatal photographs, red-eye reflections or a breeder’s prediction of future eye colour.

Updated photographs may show how the visible eye colour is developing, but they still do not establish genotype.

Buyer Advice

Before paying a deposit for a kitten advertised as DBE, request:

• the kitten’s own variant-specific DBE report;

• confirmation of every DBE variant included in the panel;

• the kitten’s KIT status where relevant;

• the individual BAER report for both ears;

• and documentation linking each result to that kitten.

Remember

A kitten does not automatically inherit DBE because one parent carries it.

Blue eyes or odd eyes do not prove DBE.

KIT does not exclude the simultaneous presence of DBE.

A premium price, pedigree claim or breeder statement does not replace an individual genetic test.

A kitten advertised as carrying a known DBE variant should have an individual result confirming that claim.

References

1. Abitbol M, Couronné A, Dufaure de Citres C, Gache V. A PAX3 insertion in the Celestial breed and certain feline breeding lines with dominant blue eyes. Animal Genetics. 2024;55(4):670–675. doi:10.1111/age.13433.

2. Abitbol M, Dufaure de Citres C, Rudd Garces G, Lühken G, Lyons LA, Gache V. Different founding effects underlie dominant blue eyes (DBE) in the domestic cat. Animals. 2024;14(13):1845. doi:10.3390/ani14131845.

3. Rudd Garces G, Farke D, Schmidt MJ, Letko A, Schirl K, Abitbol M, Leeb T, Lyons LA, Lühken G. PAX3 haploinsufficiency in Maine Coon cats with dominant blue eyes and hearing loss resembling the human Waardenburg syndrome. G3: Genes|Genomes|Genetics. 2024;14(9):jkae131. doi:10.1093/g3journal/jkae131.

4. Abitbol M, Cloquell A, Kaczmarska A, Holmes K, Lühken G, Macaulay K. Dominant blue eyes in Maine Coon cats: New PAX3 variant and updated phenotypic data. Animal Genetics. 2025;56(3):e70020. doi:10.1111/age.70020.

5. David VA, Menotti-Raymond M, Wallace AC, Roelke M, Kehler J, Leighty R, et al. Endogenous retrovirus insertion in the KIT oncogene determines white and white spotting in domestic cats. G3: Genes|Genomes|Genetics. 2014;4(10):1881–1891. doi:10.1534/g3.114.013425.

6. Strain GM. Hearing disorders in cats: Classification, pathology and diagnosis. Journal of Feline Medicine and Surgery. 2017;19(3):276–287