A Variable Monilethrix Phenotype Associated With a Novel Mutation, Glu402Lys, in the Helix Termination Motif of the Type II Hair Keratin hHb1

The study identified a novel mutation, Glu402Lys, in the type II hair keratin hHb1, linked to the hereditary hair disorder monilethrix in a French family. This mutation resulted in a variable phenotype, with some family members showing symptoms like dystrophic alopecia and follicular keratosis, while others had no visible symptoms. The mutation was absent in 50 unrelated healthy controls, indicating its specificity to the disorder. The findings underscored the genetic complexity and variability in monilethrix expression, suggesting that the disorder could be present even in asymptomatic individuals. The study emphasized the need for further research to establish a reliable genotype-phenotype correlation for monilethrix.