Keratin 6B palms and soles, and oral epithelia. Keratin 6B is associated with the PC-K6B subtype of pachyonychia congenita. Keratin 6B Keratin 6B is a type II cytokeratin, one of a number of isoforms of keratin 6. It is found with keratin 16 and/or keratin 17 in the hair follicles, the filiform papillae of the tongue and the epithelial lining of oral mucosa and esophagus. This keratin 6 isoform is thought be less abundant than the closely related keratin 6A protein. Mutations in the gene encoding this protein have been associated with pachyonychia congenita, an inherited disorder of the epithelial tissues in
Keratin used as fluorescent markers to distinguish subsets of TECs in genetic studies of the thymus. Additionally, the baleen plates of filter-feeding whales are made of keratin. Keratins (also described as cytokeratins) are polymers of type I and type II intermediate filaments, which have only been found in the genomes of chordates (vertebrates, Amphioxus, urochordates). Nematodes and many other non-chordate animals seem to only have type VI intermediate filaments, lamins, which have a long rod domain (vs. a short rod domain for the keratins). The human genome encodes 54 functional keratin genes which are located in two clusters on chromosomes 12