Epidermolysis bullosa simplex (EBS) is characterized by skin blistering due to 
basal keratinocyte fragility. In one family studied, inheritance of EBS is 
linked to the gene encoding keratin 14, and a thymine to cytosine mutation in 
exon 6 of keratin 14 has introduced a proline in the middle of an alpha-helical 
region. In a second family, inheritance of EBS is linked to loci that map near 
the keratin 5 gene. These data indicate that abnormalities of either of the 
components of the keratin intermediate filament heterodipolymer can impair the 
mechanical stability of these epithelial cells.