A KRT71 Loss-of-Function Variant Results in Inner Root Sheath Dysplasia and Recessive Congenital Hypotrichosis of Hereford Cattle

Researchers identified a loss-of-function variant in the KRT71 gene responsible for inner root sheath dysplasia and recessive congenital hypotrichosis in Hereford cattle, characterized by short, fine, wooly, kinky, and curly hair. Histopathological analysis revealed severe dysplasia in the inner root sheath of hair follicles. Genetic analysis of 17 affected and 54 control calves pinpointed a specific 8-bp deletion in the KRT71 gene, causing a frameshift and resulting in a truncated protein. This mutation was perfectly concordant with the hypotrichosis phenotype, with an estimated mutant allele frequency of 2.2% in unrelated normal Hereford cattle. The findings provide a new large animal model for similar human hair disorders and underscore the importance of genetic screening in managing hereditary conditions in livestock.