Test Detail

Feline cinnamon coat colour (multi-breed)

Dermatological · Cat

Recessive coat colour produced by a nonsense mutation in the TYRP1 gene that gives a cinnamon (or light brown) coat. It corresponds to the b^l allele of the Brown locus. It is not a disease. The test is complementary to, and not a substitute for, the clinical examination.

Inheritance pattern	Autosomal recessive with respect to B (series B > b > b^l). b^l/b^l gives cinnamon; b/b or b/b^l gives chocolate; B/- gives full colour.
Gene / Mutation	TYRP1 b^l (light brown/cinnamon): c.298C>T p.(R100*) (OMIA:001249, variant 306). Chocolate (b) is a distinct variant (c.1261+5G>A, variant 379).
Penetrance	Complete; the phenotype depends on the genotype at the Brown locus.
Sample type	sangre con edta o frotis bucal
Code	dqyy
Turnaround time	10 days
Price	63,24 €
Breeds	todas las razas

Incidence

Present in breeds that accept the brown series (for example Oriental, Británico de pelo corto, Búrmés); limited frequency data per breed.

Clinical signs

- Uniform cinnamon or reddish coat
- No systemic involvement

History

The Brown locus was described from breeding data as an allelic series B > b > b^l. Lyons and colleagues (2005) identified its molecular basis: a nonsense mutation for cinnamon (b^l) and an intron 6 splicing variant for chocolate (b).

Breeder management

- Genotype B, b and b^l in breeding animals before mating
- Do not mate two cinnamon cats unless the colour is to be fixed; a carrier mated to a clear cat produces 50% carriers
- Do not confuse cinnamon (b^l/b^l) with chocolate (b/-)

Specialist notes

Distinguishing b and b^l requires genotyping, as some panels detect only one of them. The phenotype may be masked by dilution or other loci.

References

1. Lyons LA et al. 2005, Chocolate coated cats: TYRP1 mutations for brown color in domestic cats. Mamm Genome. PMID: 16104383. OMIA:001249-9685.

Price: 63,24 € · Turnaround time: 10 days

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