Ectodermal Dysplasia (Hairlessness)

 

Gene: FOXI3

Transmission: Autosomal, dominant

For an autosomal dominant genetic disease, an animal must have at least one copy of the mutation in question to be at risk of developing the disease.  Animals with two copies of the mutation generally have more severe symptoms and an earlier onset of the disease than animals with just one copy of the mutation.  One or both of the parents of an animal with the mutation has one or two copies of the mutation.  Animals that have one or two copies of the mutation can pass the mutation on to future generations.

Mutation: Insertion, FOXI3 gene; c.57_63 dup. 7bp, p.(A23R fs STOP 219)

Medical system: Skin, dental

Breeds: Chinese Crested, Peruvian Hairless, Xoloitzcuintli / Mexican Hairless

Age of onset of symptoms: Present at birth

Hairlessness (ectodermal dysplasia) as seen in Chinese Crested, Mexican Hairless and Peruvian Hairless dogs is a condition that is characterized by scattered or absent body hair and an abnormal form of dentition known as rudimentary teeth.  Some dogs have an absence of tracheal and bronchial glands which puts them at risk for pneumonia.  The hairless individuals represent the animals that are heterozygote (M/N) for the mutation; the homozygous (M/M) situation is embryo lethal and is not seen.  Within a litter of puppies where one or both parents are hairless, there will be both hairless and normal puppies.  Breeding two hairless animals together will result in a reduced litter size.

 

References:

OMIA link: [0323-9615]

Welle MM. (2023) Canine noninflammatory alopecia: An approach to its classification and a diagnostic aid. Vet Pathol :3009858231170295.  [pubmed/37191329]

Parker HG, Harris A, Dreger DL, Davis BW, Ostrander EA. (2017) The bald and the beautiful: hairlessness in domestic dog breeds.  Philos Trans R Soc Lond B Biol Sci. 372(1713). [pubmed/27994129]

Kupczik K, Cagan A, Brauer S, Fischer MS. (2017) The dental phenotype of hairless dogs with FOXI3 haploinsufficiency. Sci Rep 7:5459. [pubmed/28710361].

Wiener DJ, Gurtner C, Panakova L, et al. (2013) Clinical and histological characterization of hair coat and glandular tissue of Chinese crested dogs. Vet Dermatol. 24(2):274-e62. [pubmed/23413772]

Drögemüller C, Karlsson EK, Hytönen MK, et al. (2008) A mutation in hairless dogs implicates FOXI3 in ectodermal development. Science 321 (5895):1462. [pubmed/18787161]