Canine Hair Curl (C1 & C2) and Risk Factor For Follicular Dysplasia in Dogs
There are three variables involved in canine coat types: the length of the coat, the presence of furnishings, and the presence of curly hair. Hair curl or wavy coat is a dominant characteristic caused by 2 seperate known mutations in the KRT71 gene. This gene codes for keratin, a protein that determines the type of hair a dog will have.
These mutations are fixed in some breeds such as C2 in Curly-coat Retrievers. However, the mutation is variable in other breeds, such as the Kuvasz. The hair curl mutations can also be accompanied by the other mutations that can change coat length and type. For example, the Airedale Terrier has both the curly coat and furnishings that are responsible for their trademark eyelashes and mustaches. Other breeds, such as the Standard Poodle, can have all three mutations, creating a long-haired curly coat with furnishings.
The C2 variant causes a slightly different type of curl or wavy coat than the first described curl variant. In addition to hair curl the C2/C2 allele is also believed to be a genetic risk factor for follicular dysplasia in some breeds.
Because the hair curl gene is dominant, a dog only needs to have single copy of either curle variant to express that phenotype. This can appear as either n/C , C/C, n/C2, C2/C2 or C/C2. Hair curl would not appear in dogs whose gene codes as recessive (n/n). A dog can carry the allele responsible for non-curly hair, and could pass the recessive allele on to any offspring. If two dogs that are both carriers of the non-curl gene are bred (n/C) or N/C2, there is a 25% chance per puppy that they will inherit the recessive alleles (n/n), resulting in a dog with non-curly hair.
Hair Curl (KRT71 gene) Testing:
Animal Genetics offers testing for 2 seperate mutations in the KRT71 gene that control hair curl or wave.
Dogs can be DNA tested at ANY age.
Animal Genetics accepts buccal swab, blood, and dewclaw samples for testing. Sample collection kits are available and can be ordered at Canine Test Now.
Testing Is Relevant for the Following Breeds:
Testing is appropriate for any type of dog suspected to carry the curl or wavy varient:
Airedale Terrier, American Water Spaniel, Bichon Frise, Border Collie, Boykin Spaniel, Chesapeake Bay Retriever, Chihuahua, Dachshund, Havanese, Kerry Blue Terrier, Kuvasz, Leonberger, Maltese, Pharaoh Hound, Portuguese Water Dog, Soft Coated Wheaten Terrier, Welsh Terrier, Wire Fox Terrier
C2 mutation associated with curly or wavy coat in Bichon Frise, Chesapeake Bay Retriever, Irish Terrier, Lagotto Romagnolo, Mudi, Poodle, Spanish Water Dog. Additional breeds may bea added as they are confermed.
Animal Genetics offers DNA testing for two different types of curl or wavy hair. The genetic test verifies the presence of both KRT71 gene mutations and presents results as one of the following:
|C/C||Curly Hair||The dog has two copies of the hair curl allele. The dog will have curly hair, and will always pass on a copy of the hair curl allele to any offspring. All offspring of this dog will have curly hair.|
|n/C||Curly Hair||The dog will have curly hair, and carries the gene responsible for non-curly hair. The dog can pass on a copy of either allele to any offspring.|
|n/n||Non-Curly Hair||The dog is negative for the hair curl allele. The dog will have non-curly hair, and will always pass on the allele responsible for non-curly hair to any offspring|
|n/C2||Curly Hair||Dog has one copy of the C2 mutation associated with curly or wavy coat. The dog can pass on a copy of either allele to any offspring.|
|C2/C2||Curly Hair||Dog has two copies of the C2 mutation associated with curly or wavy coat. The dog will have curly or wavy hair, and will always pass on a copy of the C2 allele to any offspring. All offspring of this dog will have curly or wavy hair.|
|C/C2||Curly Hair||Dog has a copy of both mutations responsible for curly or wavy coat. The dog will have curly hair, and will always pass on a copy of either C or C2 hair curl allele to any offspring. All offspring of this dog will have curly or wavy hair.|
Anim Genet. 2019 Feb;50(1):97-100. doi: 10.1111/age.12743. Epub 2018 Nov 15. A second KRT71 allele in curly coated dogs.