Follicular dysplasia (FD) leads to hair loss in Curly Coated Retrievers. Similar coat problems have also been reported in Irish Water Spaniels as well as Spanish and Portuguese Waterdogs. Our research revealed that two different genetic variants may cause curly hair in dogs. These genetic variants affected the KRT71 gene and are termed curly alleles. In most dogs with curly coat, the so called c1 allele causes the curly hair. Curly hair due the c1 allele is tightly anchored in the skin. The curls in Curly Coated Retrievers are caused by the c2 allele. The c2 allele probably results in hair shafts that break more easily and are more loosely anchored in the skin. Therefore, mechanical friction (e.g. a rubbing harness) is more likely to cause hair loss in Curly Coated Retirevers or other dogs carrying the c2 allele.
Genetic testing for the two curly alleles is offered by several genetic testing laboratories.