Hr Locus FOXI3 Hairless Gene Test (Mexican Hairless, Peruvian Hairless and Chinese Crested Type) - SINGLE ASSAY TEST

Test Overview:

The FOXI3 Hairless test detects a mutation in the FOXI3 gene associated with hairlessness in several dog breeds. This variant is responsible for the characteristic hairless phenotype seen in breeds such as the Chinese Crested, Xoloitzcuintli (Mexican Hairless), and Peruvian Hairless Dog.

The FOXI3 gene plays an important role in the development of hair, teeth, and other ectodermal tissues. A mutation in this gene causes a condition known as canine ectodermal dysplasia, resulting in reduced or absent hair and often dental abnormalities such as missing or malformed teeth.

Inheritance

Hairlessness associated with the FOXI3 mutation follows an autosomal dominant inheritance pattern with homozygous lethality.

• One copy of the mutation (heterozygous): The dog will typically be hairless, often with tufts of hair on the head, feet, and tail. Dental abnormalities are common.

• No copies of the mutation: The dog will have a normal coat and normal dentition.

• Two copies of the mutation: This genotype is lethal during early development, meaning affected embryos do not survive to birth.

Because homozygous embryos do not survive, all living hairless dogs with this form of hairlessness carry only one copy of the FOXI3 mutation.

Note: “Hairy hairless” Chinese Crested dogs have been identified as either carriers or clear for this mutation. This suggests that the genetics underlying the hairy hairless phenotype in Chinese Crested dogs is not fully understood, and that additional genetic modifiers in the genome may interact with this gene.