A NOVEL THREONINE-]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 locati on, codon 485 in a highly conserved residue position of the IATYRKLLEG E consensus motif at the end of the 2B rod domain segment of the kerat in 2e chain. The disease phenotype is consistent with the inappropriat e substitution of a proline near the end of the rod domain, because it lies near the predicted molecular overlap region of coiled-coil molec ules, which is critical for the maintenance of the structural integrit y of keratin intermediate filaments.