Categories: Integument (skin) phene

Links to possible relevant human trait(s) and/or gene(s) in OMIM: 615896 (trait) , 608245 (gene)

Mendelian trait/disorder: yes

Mode of inheritance: Autosomal recessive

Disease-related: yes

Key variant known: yes

Year key variant first reported: 2010

Species-specific name: Sphynx hairless; Atrichia

Species-specific symbol: hr; Re^HR

Inheritance: Gandolfi et al. (2010) suggested that the allelic hierarchy is best represented as KRT71(+) > KRT71(hr) > KRT71(re), where + is wild-type, hr is Sphynx hairless and re is Devon rex

Molecular basis: Gandolfi et al. (2010) showed that this hypotrichosis mutation (also known as Sphynx hairless) and the Devon rex Curly mutation (OMIA 001581) are both due to mutations in the KRT71 gene which encodes keratin 71.

Clinical features: Sphynx cats have abnormal hair shafts, with deficits in both Henle’s and Huxley’s layer of the inner root sheath and the dermal papillae, accompanied by small, curved hair follicles (Genovese et al., 2014; Mota-Rojas et al., 2021). The resulting follicular dysplasia has been attributed to the mutated form of keratin 71, ultimately giving rise to the hairless appearance of Sphynx cats (Gandolfi et al., 2010; Genovese et al., 2014). This absence of hair impedes thermoregulation by reducing insulation, making Sphynx cats sensitive to temperature extremes (Mota-Rojas et al., 2021). Sphynx cats are also prone to greasiness of the skin and higher carriage of cutaneous Malassezia (yeast) than DSH cats, attributed to their almost-hairlessness (Åhman and Bergström, 2009). IT thanks DVM student Georgia Giles, who provided the basis of this contribution in May 2023.

Breed: Sphynx (Cat) (VBO_0100230).
Breeds in which the phene has been documented. (If a likely causal variant has been documented for the phene, see the variant table breeds in which the variant has been reported).

Associated gene: