Variable keratin polypeptide profile in human stratum corneum.

Stratum corneum samples obtained from 46 members in three generations of seven families were analyzed for keratin pattern by gel electrophoresis. All these samples of apparently normal upper arm skin expressed the 55 kDa, 56.5 kDa, and 65 kDa keratin proteins; while only 28%, 20% and 48% of the samples expressed the 50 kDa, 58 kDa, and 67 kDa proteins, respectively. The keratin phenotype was identical in all members of two families (9 individuals) and variable in members of five other families (37 individuals), in whom the patterns were consistent with autosomal dominant inheritance. These results demonstrate inter-individual variations in stratum corneum keratin pattern and may reflect either polymorphism of genes coding for the various keratin polypeptides or a post transcriptional modification of mature keratins by proteolytic digestion.