Curly Coat (KRT71 gene, Selkirk Rex)

This type of coat is also known as "Rex" phenotype and stands out for being a curly coat instead of the common straight coat.

Definition

The curly coat characteristic of breeds such as the Selkirk Rex is caused by a variant in the KRT71 gene, which encodes a keratin protein essential for the maintenance of the hair structure. Alteration of this gene produces significant changes in the coat, resulting in unique phenotypes such as the curly coat of Selkirk Rex cats or even the absence of hair in other breeds.

Genetic basis

The genetic variant associated with this phenotype involves a c.445-1G>C substitution in the KRT71 gene. The allele responsible for the curly coat is known as Re^S. In the KRT71 gene, the following allelic series has been proposed: KRT71(Re^S) > KRT71(+) > KRT71(hr) > KRT71(re), where the + symbol represents the wild type, hr is related to the hairless phenotype of the Sphynx cat and the re allele corresponds to the curly coat of the Devon Rex. The curly coat caused by the Re^S allele follows an incomplete autosomal dominant inheritance pattern, meaning that the presence of a single mutated copy of the gene can produce the phenotype, albeit moderately. However, when both copies of the gene are mutated, the effect is intensified and results in a curlier coat.

Other relevant information

The degree of curl can change over time. Cats are born with a curly coat, which may become less curly as they grow, then become curlier again in adulthood. This change can be influenced by hormonal and environmental factors.

Bibliography

Gandolfi B, Alhaddad H, Joslin SE, et al. A splice variant in KRT71 is associated with curly coat phenotype of Selkirk Rex cats. Sci Rep. 2013;3:2000.