Hypotrichosis in Sphynx

Hypotrichosis means a reduced amount of hair. In sphynx cats, there is an almost complete loss of hair, which is typical for this breed. However, this characteristic trait brings with it certain health complications. The absence of hair hinders thermoregulation, making Sphynx cats sensitive to temperature extremes. Their skin is also greasier and more prone to carrying skin yeasts. Tactile whiskers are short and curled.

Hypotrichosis in sphynx cats is caused by the c.816+1G>A mutation in the KRT71 gene, which encodes keratin 71. The mutation results in dermal papilla deficits and hair follicle dysplasia.

The mode of inheritance of the mutation is autosomal recessive. Hypotrichosis occurs when an individual inherits the nakedness trait (HR) from each parent; the genotype of a naked individual is HR/HR. Individuals with a genetic test result of N/HR are carriers of nakedness. Individuals with a result of N/N do not carry nakedness. A naked individual may also carry the HR/DR genotype – the DR allele is not detected by this test.

The genetic test can clearly reveal the genotype of the animal and is a useful tool for breeders to prevent unintentional breeding of affected kittens.

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References:

Gandolfi, B., Outerbridge, CA., Beresford, LG., Myers, JA., Pimentel, M., Alhaddad, H., Grahn, JC., Grahn, RA., Lyons, LA. : The naked truth: Sphynx and Devon Rex cat breed mutations in KRT71. Mamm Genome 21:509-15, 2010. Pubmed reference: 20953787