How the directory is compiled, the four grades of evidence, and the eye codes it writes
The material on this page is drawn from the Global Cat Health Survey 2026, which is where its sources and its declarations of interest are set out in full.
Cat Health Survey 2026 Back to the survey The register itself How it is compiled EMS codes What it holds Latent carriers Catteries Who to test Observations SourcesAn identified variant is a sequenced one. A change in PAX3 that a laboratory has found and a publication has named. Six are named in the work this register holds.
An unidentified variant is a dominant blue eye variant that has not been sequenced, whether it lies in PAX3 or in another gene. It is not an absence. The trait is visible in the animals, it descends as a dominant, and in many cases the breeders who hold it have given it a name, which is why this register carries those cats under a named founder line. Until a line is sequenced the gene is not known either, so calling such a line a PAX3 line would claim more than the record holds. What is missing is the laboratory result, and with it any test a breeder could buy.
So a line recorded here as having no variant identified is a line not yet sequenced. It never means that the cats in it show nothing.
Every relationship in this directory is computed from one field, parents, on every build. The same links are walked twice, and the two directions answer different questions.
Both directions fold a line into the variant sequenced within it, so one variant recorded two ways is never read as two. Neither direction is evidence that an animal carries anything: descent puts an allele within reach and a heterozygote passes it to half its offspring.
A finding is a claim about the evidence that names what would overturn it. Each is numbered, dated and computed against the register on every build, so it cannot drift from the record it rests on.
A cat registered XSH or XLH has not changed breed. The codes mean experimental shorthair and experimental longhair, and a registry uses them for an animal of a recognised breed whose colour or eye colour its standard does not permit. A blue eye is exactly such a feature, so the trait this directory follows is itself a reason a cat is written XSH or XLH.
The register therefore groups these cats by the programme they were bred in and not by the code on the certificate. A British cat registered XSH sits in the British group; the experimental longhairs of the Blue Ridge programme sit with the Maine Coon.
Where a cat's own code carries a pointing factor, its blue eye has an ordinary cause and the register does not read it as evidence of a variant. The codes are 31 Burmese, 32 Tonkinese or mink, and 33 colourpoint, and each lightens the eye by itself.
The rule extends to the breed group. A breed of the colourpoint series is not a group of unknown variant unless a known variant has been bred into it. One chart in this register, thirty-six cats headed Dominant Blue Eyes in Mink Ragdoll, is of that kind: sixteen mink, eleven point, two sepia and not one solid, and every one of its fifteen blue or odd cats carries either a pattern of the colourpoint series or white: a mink, point or sepia coat, or white spotting, each of which already accounts for a pale or an odd eye. One of the fifteen is a blue bicolour rather than a mink, and it is the white that answers for it. Those cats are held with the eyes their sources give them and are not counted as a variant anywhere in this directory.
Where a registry codes both, the record cannot separate them. A handful of cats here carry a pointing code and a dominant blue eye code on the same line, for example BSH as 09 11 33 68. Two causes of a pale eye then stand on one animal. The register records both codes, notes the double cause on the cat, and reads the animal as evidence neither way. Only a genotype separates the two.
A crossing does not apply across two breed groups. Belle Ayr holds British Shorthairs carrying DBEALT and Maine Coons descending from DBERE; the two never meet, because no mating in that cattery could bring them together.
Every table in this directory that reports a crossing, a possible crossing or a variant standing above a cattery's cats is therefore keyed on the cattery and the breed group, never on the cattery alone. Breeds that do interbreed are treated as one group, so the British Shorthair and the British Longhair are one population, and the experimental longhair is counted with the Maine Coon.
Every entry carries one of four grades. The grade describes what is known about that cat, not about its line. A cat whose founder was genotyped is line-traced and not genotyped, because the cat itself has no result.
A name is reproduced as its source wrote it. The same cat reaches the survey from a registry certificate, a breeder chart and a pedigree database, and the three rarely agree on spelling, on a title or on an accent.
Two conventions follow from that. The breed is written Céleste, as its registry writes it; where the word appears without the accent it is a line label or a chart name reproduced from its source. A cat carrying a registry title, CH or GIC, keeps it in its own name and is found under the name without it. Where two spellings turn out to be one animal the records are joined and both spellings are kept on the surviving record, so a search under either still finds the cat.
Many charted cats have no name. On one breeder chart entered here, sixteen of twenty-four kittens are labelled only "Girl 1" or "Boy 2", two of the sixteen carry the same label, and every one of the thirteen second-generation kittens is unnamed. A directory keyed on names cannot hold them. Every entry therefore carries a stable number, and a cat shown in italics throughout this directory is a cat with no name in its source, entered under the source's own position label.
No name of any person, no address, no ownership and no price. Catteries appear by prefix only, a prefix being a trade name printed on every pedigree the cattery issues. No cat is entered that is not already named in a published source or in a document supplied to the survey for the purpose.
Every cat page carries a numbered chain and a Save as PDF button. The chain is computed at each build from recorded parent links, never typed.
A genealogy drawing answers a different question from the one most readers arrive with. It shows everything above an animal at once and leaves the reader to find the part that matters. What a breeder actually asks is how this cat is joined to the trait, and how many steps away it is. That is a single chain, so each cat page writes it out as a numbered list before the drawing.
The chain stops at the most informative animal it can reach, in this order: the cat itself where a laboratory has tested it; otherwise the nearest genotyped ancestor, because a result fixes what descends from it; otherwise the nearest founder or the nearest ancestor carrying a variant the survey has adopted. It closes by saying which of those it reached, and whether the animal at the end has a laboratory result or only a descent. Those are different things and the sheet says which one it is holding.
Where no parent link reaches any of them, the page says so in those words and states what the record rests on instead: a line attributed by a source, a variant a source claims and the survey does not adopt, or no recorded parent at all. A cat with no path is not hidden and not quietly left out of the list.
Save as PDF prints the sheet. There is no stored file and no separate document to go stale: the button opens the browser's own print dialogue and a stylesheet lays the page out on A4 landscape. What comes out carries the chain, the genealogy, the source the record rests on, and this directory's name and address. A page of genealogy handed to somebody with no provenance on it is worth very little, and provenance is what the survey is about.
The sheet is a snapshot and says so on its own face. The register grows every week, so a printed chain can be shorter than the current one; the address on the footer is where the current version lives.
Four registries code this trait and no two of them code it the same way. Each block below is quoted from that registry's own document. They are not merged.
Many certificates print the eye in words as well as in code: "cinnamon with blue eyed", "blue with white with odd eyes", "black-white-blue-eyed". Where both appear, the pair is the evidence of what the code means, and it is the only way a cat coded 61 under one system and 68 under another can be reconciled at all. The register records the words beside the code for every cat that has them.
The GCCF is the only registry in the world that records which variant a cat carries on its own registration record. It does so through GEMS, the coding system that assigns every registered cat a string identifying its breed, its coat colour and its eye colour. The breed is therefore already in the code, so which breed a variant sits in can be answered for any individual cat the GCCF has coded.
The eye-colour codes are 61 blue, 63 odd-eyed, 67 Siamese eye colour, and, added for this trait, 68 dominant blue eye odd-eyed and 69. Note code 67: the GCCF does distinguish colourpoint blue from dominant blue eye blue at the coding level. Alongside those sit four variant codes: 161 Unknown, 162 Celestial (DBECEL (Roxi)), 163 Altai (DBEALT), 164 Rociri Elvis (DBERE). They are classification codes and not counts: 162 identifies a cat as carrying DBECEL (Roxi), it does not say how many such cats there are. The tracking went live in June 2025, the IT report to Council recording that work to introduce it “is now live”.
Two numbering systems are in use and they disagree. A bare number is not a variant name.
| Variant | GCCF GEMS code | Laboratory number used in China |
|---|---|---|
| Unknown or unidentified | 161 | no number |
| DBECEL (Roxi), Céleste, Roxi | 162 | DBE-1 |
| DBERE, Rociri Elvis | 164 | DBE-2 |
| DBEALT, Altai | 163 | DBE-3 |
| DBEAGO, Agostino | no code | DBE-4 |
| DBEcDc | no code | DBE-5 |
| DBExHW, Xin-He Winnie | no code | DBE-6 |
The two systems run in different orders. DBE-2 is Rociri Elvis in the laboratory numbering, while the GCCF's second named variant, 163, is Altai. A number given without naming the system it belongs to cannot be read safely, and the two systems are already in circulation together: a cat may hold a GCCF registration coded 163 and a test report from the same laboratory reading DBE-3, which agree, or a report reading DBE-2 against a GCCF code of 164, which also agree. Any pair that looks wrong may simply be two systems, and any pair that looks right may be a coincidence of numbering.
Recommendation. Any record of this trait should give the variant by name, and give the numbering system alongside any number. Three of the six variants have a number in one system and none in the other.
Other registries code the trait, so the GCCF's scheme is distinctive rather than unique. Pedigree certificates obtained by the survey show three further systems in use. ARBC issues code 60 and glosses it on the certificate itself, in English, as “dominant blue eyes”, with 08 for the accompanying white spots. WFA issues a 68 series, with 68b for odd eyes and 68c to 68e for latent carriers, the same series as the TopCat and Felinological Federation of Russia Altai standard. REFR marks BE on the registration number, expressly including kittens that show no blue eye. And TICA has no code at all: its registration form records the eye as free text in a box, so a TICA pedigree cannot be queried for this trait in any way.
The distinction that survives is a narrow one and it is the one that matters. ARBC, WFA and REFR record the phenotype, or the fact of carriage. Only the GCCF records which variant. A code meaning “this cat has a dominant blue eye” cannot prevent the mating this directory is about, because the harm arises when two different variants meet and every one of those cats carries the same code.
A latent carrier is codable, and one registry codes it. WFA issues 68c to 68e for a cat carrying the variant without a blue eye, and a certificate held by the survey codes an entire litter of three as 68e. The consequence is that the animal hardest to identify by eye, and therefore the one most likely to disperse the variant unnoticed, is the animal for which a code already exists and is almost never used. The survey recommends that any registry recording the trait adopt a latency code and require it, since one is available to copy rather than to invent.
One genealogy, three ways of recording the same eye, and a fourth cat that defeats all three. The blue-eyed Maine Coon breeder-compiled genealogy carries about ninety cats and records the trait three different ways at once.
And a white cat sits in the middle of the line. Osiride Dolce Blu, MCO w 62, is a white cat bred to a blue-eyed daughter of the line, producing one odd-eyed and one blue-eyed daughter on the same day. Dominant white causes a blue eye by a route that has nothing to do with PAX3, so from that mating forward no cat in this branch can be attributed to the variant by eye colour, and only a test can separate the two causes.
A registry counting blue-eyed Maine Coons in this line would find them under three different codes and would miss the ones under none.
Read as a ban, the British Shorthair policy looks like a refusal. Read against the rest of the scheme, it is a separation mechanism. A blue-eyed or odd-eyed cat of British appearance is not turned away: it is registered on the Reference Register with no progression, as no recognised breed. The animal is recorded, its parentage is certified, and it is kept out of the breed's active gene pool. The variant codes then do the tracking: 161 unknown, 162 Céleste, 163 Altai, 164 Rociri Elvis, on the cat's own registration record. Descendants that are not themselves blue-eyed are overstamped “DBE in the pedigree”, so latency travels with the paperwork.
| Date | What the GCCF did |
|---|---|
| 23 February 2025 | Council adopts the registry-wide import rule: an importer of any blue-eyed or odd-eyed cat that is not white, bicolour or Himalayan colourpointed must submit a DNA result identifying the causal gene, or clear results for all known DBE mutations |
| 22 February and 5 March 2025 | Persian and Exotic joint policy approved, placing any Persian or Exotic with the trait on the Reference Register and on the Genetic Register; Maine Coon registration policy approved |
| June 2025 | Variant tracking goes live. The IT report to Council records that the work to introduce it “is now live” |
| 28 June 2025 | Maine Coons exhibiting the trait may not be registered or imported from other registries. On the same date the Korat and Thai change is voted, 83 per cent in favour, none against |
| August 2025 | GEMS code list published carrying 161 to 164, two months after DBEAGO was published without a code |
| 4 September and 22 October 2025 | Genetics Committee minutes record the difficulty that “all known DBE mutations” is a set the registry cannot itself enumerate |
| 12 November 2025 | British Shorthair position takes effect: blue-eyed and odd-eyed cats of British appearance to the Reference Register with no progression |
| 27 June 2026 | Council approves a revision of the British Shorthair policy, recorded in the policy's own amendment history |
The British Shorthair policy has been revised three times in eight months: effective 12 November 2025, revised 29 April 2026, and revised again with Council approval on 27 June 2026. An instrument rewritten at that rate has not settled. The survey therefore quotes the June 2026 text and fixes its own entry at 7 August 2026.
What the minutes show as open, in the registry's own words. Two questions are recorded in committee papers and are not closed in the text standing at the census date.
And the variant codes cover half of what exists. The scheme carries four numbers, 161 unknown, 162 Céleste, 163 Altai, 164 Rociri Elvis, so it can name three of the six identified variants. DBEAGO was published in June 2025, two months before the code list, and has no code. The two Chinese variants identified later that year have none. The consequence falls on 161: a cat coded unknown may carry a variant nobody has identified, or a variant that has been identified and not yet numbered, and the record cannot tell those two apart. A coding scheme that names variants must be extended each time one is published, or the unknown code silently absorbs the difference.
Sources: GCCF Registration Policy for British Shorthair Cats, June 2026 revision, and its amendment history in the Breed Matters Binder; Genetics Committee minutes of 4 September and 22 October 2025; Council binders of 22 February 2026 and 27 June 2026; GEMS code list, August 2025.
That is the combination this directory recommends everywhere else: record the animal, code the variant, and control the mating rather than the cat.
A registration ban does the opposite, removing the animal from the record while leaving it in the population; a reference register with a variant code keeps the animal out of the breed and keeps it in the record, and only the second leaves anything for a registry, or anyone else, to act on later.
Rules and codes: GCCF Registration Policy for British Shorthair cats, the Persian and Exotic joint policy, the Maine Coon, Korat and Thai, Bengal, Devon Rex and Tonkinese policies, the Rules at section 1, 7f(vii) and 7g(vii), the Genetics Committee minutes of 4 September and 22 October 2025, and the GEMS code list of August 2025. Every statement above is taken from one of those documents. No reason for any decision is attributed to the registry here, because the survey holds no document in which the registry states one.
The gap reaches the GCCF's own import rule, which asks for a clear result for “all known DBE mutations”: at the date of the August 2025 code list, all known DBE mutations numbered six and the scheme could record three.
One of the four names is also wrong in kind. Codes 163 and 164 are Altai and Rociri Elvis, the population and the line in which those variants arose, which follows the convention. Code 162 is Celestial, a breed created years after the variant it names. The reference is unambiguous, since Céleste, Celestial and Celestial British are one breed, so the fault is in kind rather than in reference. That departure has been carried into a registry database, where correcting it means recoding every cat already coded.
The codes also make a count possible for the first time. Every cat the GCCF has coded 162 is a recorded DBECEL (Roxi) cat and every cat coded 163 is a recorded DBEALT cat, so counting them is a database query. No other registry is in a position to run it, the tracking has been live since June 2025, and no figure has ever been published.
None of it asks for a test. It asks a registry to record which variant a cat carries in a field of its own, separate from the eye code, and to gate matings on that field rather than on eye colour, because a latent carrier has no blue eye to write a rule about. It adopts the GEMS codes as they stand, keeps 161 and gives it a suffix where the line is named, and marks whether the entry rests on a laboratory result or on the pedigree. It is set out in full, with the figures and with the scheme applied to every record in this directory, on the proposal page, which is the only place it is stated.
An entry carries the EMS code as the source wrote it, in whichever of the systems below that source uses. Nothing is translated from one system into another, because the translation is the thing in dispute. 3860 of the 4225 entries carry a code at all. What follows is every eye code that appears in this directory, counted from the entries themselves.
| Code | What the issuing registry means by it | Occurrences |
|---|---|---|
| 61 | Blue eyes. WCF and FIFe, the mainstream code, and the one that carries no statement about why the eye is blue | 127 |
| 63 | Odd eyes, in the same system | 106 |
| 63/1 | Dominant odd eyes. Written on the Azul chart only | 1 |
| 60 | Dominant blue eyes, glossed in English on the certificate itself. ARBC, and the only code in any system that names dominance outright | 10 |
| 68 | Blue eyes. WFA and TopCat, in a series written for this trait | 510 |
| 68b | Odd eyes, the eye that is not blue being yellow | 2 |
| 68e | Latent carrier, by the colour of the eye that is not blue | 3 |
| 69 | Odd eyes, in the 68 series | 132 |
These columns count occurrences of a code, not cats. A handful of records carry two conflicting source codings, an FBU certificate against a breeder chart for instance, and such a record appears under each code it was given. A code carrying no eye figure at all is the commonest case in this directory and is not an absence of the trait: it is a registry that does not code the eye, or a source that did not print the full code.
The white codes are set out beside them because the coat decides whether a blue eye is evidence of anything. Where white reaches the head an ordinary explanation for a pale eye is already available, and the coat-exclusion rule set out below turns on exactly these figures.
| Code | Grade of white | Occurrences |
|---|---|---|
| 01 | Van, white over almost the whole cat | 78 |
| 02 | Harlequin | 117 |
| 03 | Bicolour | 448 |
| 09 | Unspecified white, a locket upward | 846 |
| 08 | Residual white, in the ARBC system | 7 |
| bicolour with BOTH eyes blue | A DOMINANT BLUE EYE STRAIN. The classic white spotting gene, S or Ws at KIT, covers an eye during development where the white happens to fall. That gives an ODD eye and it does not give two blue ones in a traditional bicolour, so the coat does not account for the phenotype |
| bicolour with ONE blue eye | THE WHITE SPOTTING TRAIT, AND NOT EVIDENCE OF A VARIANT. The distribution of white is stochastic and is not inherited as a unit: two ordinary-eyed bicolour parents can produce an odd-eyed kitten whose littermate carries the same alleles and has ordinary eyes. THAT LOOKS LIKE A TRAIT SKIPPING A GENERATION AND IT IS NOT ONE |
| what follows for the deduction | an odd-eyed bicolour IS EXCLUDED from seeding a latent-carrier deduction, exactly as a dominant white cat is, because there is nothing about its eye left to explain |
| what the rule does not do | IT NAMES NO VARIANT. Which dominant blue eye is not deducible from a coat code, and this register still adopts none without a genotype or a trace to a named founder. Nor does it exclude a variant in an odd-eyed bicolour: such a cat looks the same whether or not it carries one |
| a code is not the cat, ADDED 25 AUGUST 2026 | A CODE WITHOUT A WHITE SYMBOL IS NOT A CAT WITHOUT WHITE. A locket or a chin patch is routinely left off an EMS code, and one cattery's own genetics article calls the locket A TRAITMARK OF THE DOMINANT GENE rather than an accident. Photographs in this register show white chins and chests on cats whose codes carry no white symbol at all. THE RULE REPORTS WHAT IS RECORDED, NOT WHAT IS THERE, and the honest form is NO WHITE RECORDED rather than NO WHITE |
| placement beats grade, ADDED 25 AUGUST 2026 | A CODE GIVES THE GRADE OF WHITE AND NOT ITS PLACEMENT, AND PLACEMENT IS WHAT THE RULE ACTUALLY TURNS ON. Photographs in this register show bicolours whose PIGMENT COVERS BOTH ORBITS with the white running as a blaze between them, AND BOTH EYES BLUE. The code reads 03 and the tier says excluded; THE PHOTOGRAPH SAYS THE WHITE NEVER REACHED EITHER EYE. Where a photograph exists it should be looked at |
| the same reasoning on a cat with no white on the head | IT EXTENDS BEYOND BICOLOURS. On a solid, a tortie or a locketed cat with NO WHITE ON THE HEAD, white spotting cannot have paled either eye, and a blue or odd eye on such a cat has no ordinary explanation. The clearest case in this register is a chocolate tortie with a clean split face WHOSE BLUE EYE SITS IN THE DARKEST FUR ON THE ANIMAL |
| what the rule still cannot see | A SECTORAL IRIS. This register holds cats with ONE EYE PART BLUE AND PART ORANGE, and one with both eyes divided that way. A PARTIAL EFFECT WITHIN ONE EYE IS A FEATURE OF THE IRIS AND NOT OF THE COAT, and no coat rule addresses it. One cattery calls this POLYCHROMIC and classes it among the dominant phenotypes |
| 61 before the dominant codes | MAY BE A DOMINANT BLUE EYE RECORDED UNDER THE ONLY CODE THEN AVAILABLE, OR MAY BE AN ORDINARY BICOLOUR. The code does not decide and the date does not decide |
| when it is adopted | only where the cat links by recorded descent to a NAMED variant. A cattery attribution is not a name and a red label on a chart is not a descent |
| precedence, where BOTH eyes are blue | THE BOTH-BLUE BICOLOUR RULE DECIDES AND THIS ONE STANDS DOWN. A 61 on a cat with two blue eyes, a white spotting code, no dominant white and no colourpoint is not ambiguous. THIS RULE GOVERNS ONLY THE ODD-EYED AND THE SINGLE-BLUE CASES |
| when it is not | in every other case the code is recorded, the ambiguity is recorded, AND NOTHING IS ADOPTED. A 61 on a cat that also carries a white code has an ordinary explanation available and that is enough to stop the survey adopting the other |
| 61 | blue eyes |
| 63 | odd eyes |
| 63/1 | dominant odd eyes, on the Azul chart only |
| 60 | DOMINANT blue eyes, distinguished from the ordinary 61 |
| 08 | the little white spots that accompany it |
| 68 | blue eyes |
| 68a | odd eyes, the non-blue eye green |
| 68b | odd eyes, the non-blue eye yellow |
| 68c to 68e | LATENT CARRIERS, by the colour of the non-blue eye |
| 68f to 68g | sectoral heterochromia, disqualified from breeding |
| 08 | residual white |
| none | the eye is typed as free text in a box reading 'Blue'. There is nothing to search on, so a TICA pedigree cannot be queried for this trait |
Four registries code this trait, and two of them code it well: between them ARBC and the WFA and TopCat series already publish everything a breeder would need. What is missing is agreement: the same animal is 60 in one system, 68 in another and 61 in a third, and a pedigree does not say which system it is written in, so a cat sold across a border arrives with a code its new registry reads differently or cannot read at all. One agreed code for the trait and one for carriage would cost nothing, and both already exist to be copied.
And a 61 is not a stable category. One cattery's own published pedigree writes 61, the ordinary blue-eye code, on three consecutive generations and annotates every one of them with the name of a dominant variant, so there the code is used knowingly for animals the cattery states carry a variant. A second case is plainer still: one cat in this register is written 61 on his cattery's website and 68 on his registry pedigree, and the website is the earlier record. Another sheet writes the same descending trait as 61, then 60, then 68, then 68, then 69 across five generations and three registries, while a fourth registry writes the same animals out in words as "dominant blue eyes". Where a coat carries no white, a 61 in this register is a candidate 68, the older the record the more so, and no count drawn from 68 and 69 alone should be read as complete.
Code 69 tracks something real, and it segregates. The register holds ten litters containing both a 68 and a 69, and a genotyped cat coded 69 whose two full sisters, confirmed to carry the same variant, are coded 68 and nothing at all. The registries disagree about what to call it, not about whether it is there. On one certificate it stands against a cat glossed "odd eyed" whose colour field carries an "x" for unrecognised, and the WCF list places 69 under non-recognised eye colours, which describes the code's standing in that system rather than the animals carrying it.