Blue Maine Coon: Dilute Genetics and What the Colour Means

What Makes a Blue Maine Coon Blue, and Is It a Separate Breed?

A blue Maine Coon is an ordinary Maine Coon whose black pigment is diluted to a soft grey-blue by two copies of a recessive variant in the MLPH gene. Blue solid, blue tabby and blue smoke are all accepted in the CFA Maine Coon standard, and size, temperament, health and care are the same as in a Maine Coon of any other colour.

KnowCatHub Editorial Updated 30 September 2026 All breeds

A blue Maine Coon is a Maine Coon whose coat colour has been softened from black to grey-blue by the dilution gene.

The colour is recognised in the CFA Maine Coon standard. Nothing about the cat's size, temperament, health or care changes because of the colour.

What Does the Dilution Gene Do?

The dilution gene is MLPH, and its dilute variant, written d, is autosomal recessive. A cat must carry two copies (d/d) for the colour to show, which is why two black Maine Coons that each carry one hidden copy can produce blue kittens.

In a d/d cat, the melanin granules in the hair are clumped and irregularly distributed rather than evenly spaced. This changes how light reflects from the hair, turning what would be dense black into soft grey-blue.

The underlying colour is still genetically black (B at the brown locus). The dilution gene modifies how the pigment appears, not which pigment is produced.

Colour class: Blue, a recognised CFA Maine Coon colour
Genetics: Black (B) + two copies of the MLPH dilute variant (d/d)
What the gene does: Clumps melanin granules, changing black to grey-blue
Accepted patterns: Blue solid, blue tabby, blue smoke, blue and white, and others
What does not change: Body type, temperament, health, size, grooming, maturation speed

Which Blue Varieties Exist?

The Maine Coon standard accepts blue across multiple pattern classes. A blue Maine Coon can be solid blue, blue classic tabby, blue mackerel tabby, blue smoke, blue and white and other combinations.

All share the same grey-blue base colour. The pattern determines whether the blue appears as a uniform solid, as tabby stripes against a lighter blue ground, or as a silvery undercoat showing through a blue outer layer (smoke).

Three patches of long grey-blue cat coat: plain even blue, blue with darker swirls, and blue parted over a pale silvery base — Solid, tabby and smoke all carry the same diluted black, so a colour class on the papers names the pattern while the grey-blue itself stays constant.

Does the Blue Coat Need Different Care?

No. Dilution changes only the pigment inside each hair, so the coat is the same long, shaggy Maine Coon coat in any colour, and it needs combing a few times a week for most of the year, with more frequent sessions while the undercoat is shedding.

What Should You Check When Buying a Blue Maine Coon?

Because the colour changes nothing else, the checks for a blue kitten are the ordinary Maine Coon checks plus two that come from the colour itself: whether the registration names a blue colour class, and whether blue is being sold as rare. Blue is one of the colours the standards accept, so a price premium for it is the seller's pricing decision rather than a sign of a scarcer or different cat.

The health screening is the Maine Coon set: a dated heart scan of each parent for hypertrophic cardiomyopathy, DNA results for spinal muscular atrophy, and attention to hip dysplasia in a heavy cat. None of it is affected by coat colour.

Registration as a Maine Coon in a blue colour class, with both parents named
A price that reflects the kitten and its parents rather than a premium for a standard colour
A dated heart scan for each parent and DNA results for spinal muscular atrophy
The kitten's own temperament and coat, seen in person, since colour predicts neither

Common Questions

Is a blue Maine Coon a separate breed?

It is a colour variety of the Maine Coon. Two copies of the recessive dilution gene turn black pigment grey-blue, and nothing else about the cat changes.

What makes a Maine Coon blue?

Two copies of a recessive variant in the MLPH gene (d/d) leave the pigment granules in each hair unevenly clumped, so dense black appears as soft grey-blue.