Hypotrichosis (KRT71 gene, Sphynx)

Hypotrichosis related to the KRT71 gene is characteristic of breeds such as the Sphynx, which has sparse hair and short, curly whiskers.

Definition

Hypotrichosis with short, curly whiskers manifests as a lack of hair on much of the body, although some cats may have tufts of hair in specific areas, such as the chest, ears or tail. Whiskers are generally short and curly, a characteristic influenced by mutations in the KRT71 gene. These mutations affect hair follicle formation and hair structure, as the KRT71 gene encodes a protein involved in the formation of keratin intermediate filaments in the hair follicle.

Genetic basis

In the case of the Sphynx cat, the c.816+1G>A variant has been identified in the KRT71 gene that affects hair formation and stability. The allele responsible for this trait is known as KRT71^hr. The following allelic series has been proposed in the KRT71 gene: KRT71(+) > KRT71(hr) > KRT71(re), where the + symbol represents the wild type and re is related to the curly coat in the Devon Rex. This trait has an autosomal recessive inheritance pattern, meaning that two copies of the variant are required for the trait to be expressed. However, the presence of a single copy of the variant can be passed on to offspring with a 50% probability.

Other relevant information

The identification of mutations in the KRT71 gene allows breeders to carefully select animals for breeding, ensuring that desired traits, such as hairlessness in Sphynxes or curly coats in Devon Rexes, are maintained.

Bibliography

Gandolfi B, Outerbridge CA, Beresford LG, et al. The naked truth: Sphynx and Devon Rex cat breed mutations in KRT71. Mamm Genome. 2010;21(9-10):509-515.