A novel theonine → proline mutation at the end of 2b rod domain in the keratin 2e chain in ichthyosis bullosa of siemens

We report a novel mutation in a case of ichthyosis bullosa of Siemens that results in a threonine → proline substitution in a novel location, codon 485 in a highly conserved residue position of the IAT-YRKLLEGE consensus motif at the end of the 2B rod domain segment of the keratin 2e chain. The disease phenotype is consistent with the inappropriate substitution of a proline near the end of the rod domain, because it lies near the predicted molecular overlap region of coiled-coil molecules, which is critical for the maintenance of the structural integrity of keratin intermediate filaments.