KRT31 and Pseudofolliculitis barbae: Interestingly, mutations in type II hard and soft hair keratins (KRT75, KRT81,83,85,86), but not type I hair keratins (KRT25-28, KRT31-40), have reported associations with other genetic hair disorders such as Monilethrix, pseudofolliculitis barbae, and hair ectodermal dysplasia26,31,35.