Curly Coat Dog

Curly coat

Like all mammals, a dog’s hair is primarily composed of the protein keratin. Mutations in genes responsible for encoding keratin can alter the shape and texture of individual hairs, which in turn affects the overall appearance of the coat. One example is a recessive mutation in the keratin 71 (KRT71) gene, which causes the development of a curly coat instead of a straight or wavy one. 

Two variants of the KRT71 mutation have been identified. The first variant, designated c¹, is specific to the Portuguese Water Dog. The second variant, c², is found in breeds such as the Bichon Frise, Chesapeake Bay Retriever, Curly Coated Retriever, and Spanish Water Dog, all of which are known for their characteristic curly coats. Not all curly‑coated dogs carry these variants, indicating that additional curly‑coat mutations likely exist but have not yet been discovered. 

Dogs that inherit two copies of a KRT71 mutation typically develop a curly coat. Dogs that also carry the recessive long‑hair mutation in FGF5 may show longer or more pronounced curls due to the combined effect of both genes. 

For the c2 KRT71 variant, the underlying mutation involves a duplication‑type structural change in the DNA. With our current design and the platform of the test, it is not possible to distinguish between dogs that carry one copy of the mutation (carriers) and dogs that carry two copies (affected). In such cases, the test report will indicate that the mutation is present, without specifying whether the dog is a carrier or genetically affected. 

Relevant tests

• H681
• H921