The Cornish Rex is defined by a distinct recessive rexoid mutation (r) at a locus non-allelic to the Devon Rex gene (re), resulting in a fine, wavy coat with reduced awn and guard hairs that expresses all pigmentation genotypes normally in terms of EMS color classification. FIFe standard accepts all colors and patterns for CRX, spanning the full B-locus allelic series, colourpoint (cs/cs) variants, all tabby patterns, and the O-locus tortie combinations, placing identical demands on feline genetics program management as DRX. An EMS color calculator for Cornish Rex breeders should flag the non-allelism of r and re as a first-line outcross compatibility check, since CRX × DRX matings produce entirely straight-coated F1 offspring.
Common recessive carriers
The r allele is recessive; heterozygous (R/r) cats are straight-coated. All color recessives (b, bl, d, cs) are present in CRX populations. The Cornish Rex has historically undergone outcrosses to British Shorthair, Siamese, and other breeds, introducing a broad allelic diversity across color loci.
Breed-specific restrictions
No color or pattern restrictions apply. The r allele is non-allelic to the Devon Rex (re) and the German Rex (rg) — crosses between these breeds produce straight-coated double heterozygotes. Dominant White (W) is accepted. Amber (e) is not specifically listed in FIFe CRX standard.
Pattern quirks
All tabby patterns (22, 23, 24, 25) are accepted. The reduced coat structure of the Cornish Rex may render tabby pattern contrast less visually distinct compared to full-coated breeds, but phenotypic assessment for EMS coding follows standard rules.
CRX nBlack (solid)CRX a 25Blue Ticked TabbyCRX bChocolate (solid)CRX f 23Black Tortie Mackerel TabbyCRX n 33Seal ColourpointCRX ns 22Black Silver Classic TabbyFree online tool to predict kitten coat colors based on Mendelian genetics. Select the breed and appearance of sire and dam to see color probabilities.
Enter the appearance of both parents to calculate color predictions.