Faculty Opinions recommendation of Autosomal-dominant woolly hair resulting from disruption of keratin 74 (KRT74), a potential determinant of human hair texture.

The study by Shimomura et al. identified a mutation in the keratin 74 (KRT74) gene as responsible for autosomal dominant woolly hair in a Pakistani family. This mutation, found in exon 1 of the KRT74 gene, was linked to the type II keratin gene cluster and resulted in a single amino acid change affecting all affected family members. The research highlighted the role of keratin 74, specifically expressed in the Huxley's layer of the inner root sheath (IRS) of hair follicles, in determining hair texture, such as curliness. The study also noted significant differences in single-nucleotide polymorphisms (SNPs) in the keratin 71-74 region between people of African and European descent, suggesting these genes may play a crucial role in human hair curl phenotype. This research provided insights into the genetic basis of hair texture variations and the importance of the IRS in hair follicle function.