Dog Hairlessness – Canine Ectodermal Dysplasia
Dog hairlessness is an inherited trait caused by a genetic mutation in the DNA. Worldwide recognized hairless dog breeds are the Chinese crested dog, the Mexican hairless dog and the Peruvian hairless dog. Mexican hairless dog is also known as the Xoloitzcuintli, and it was considered sacred by the Aztecs. Hairless dogs’ phenotype is classified as canine ectodermal dysplasia (CED). Its characteristics are missing or abnormally shaped teeth in addition to a hair coat that is sparse or absent. CED is inherited in an autosomal dominant inheritance pattern and it is linked to chromosome 17 in Mexican hairless dogs, Peruvian hairless dogs and Chinese crested dogs.
All of those three dog breeds share the same mutation, and researchers say it probably appeared in Mexican hairless dog 4,000 ago and was eventually passed on the other two breeds due to breeding program. As the researches revealed, mutation responsible for hairlessness in dogs is a seven base pairs insertion of genetic code into a gene known as FOXI3. This form of mutation is identified in all hairless dogs.
Since it is inherited as an autosomal dominant trait, heterozygous dogs’ phenotype appears as hairless and can vary in stages of hairlessness. Hair appears mostly only on a crest on the head, feet and tail. Dogs which do not posses the mutated gene are reffered to as powderpuffs. Characteristic of the powderpuffs is that their body is covered in long, silky coat. Homozygousy is lethal and when the dog contains one pair of mutated genes, it dies already during embryogenesis.
A specific form of dog hairlessness is inherited as an autosomal recessive trait, which was identified only in the American Hairless Terriers. Homozygousy in American Hairless Terriers is not lethal.
Some health problems are associated with hairlessness, and those health probles are not necessarily genetic. They are mostly skin poblem and allergies. Hairless dogs are more likely to get sunburn and skin cancer, due to lack of natural protection to sun. In dominant hairless dogs, tooth problems can occure (most commonly molars).
AnimaLabs offers genetic testing for hairlessness for Chinese Crested, Mexican Hairless and Peruvian Hairless.
Following diagram shows way of inheritance of hairlessness:
Turnaround time: 15 business days