A novel mutation in the 2B domain of keratin 2e causing ichthyosis bullosaof Siemens

Ichthyosis bullosa of Siemens (IBS; MIM: 146800) is an autosomal dominant d isorder of keratinization characterized by epidermolytic hyperkeratosis wit hout erythroderma. The clinical features are less marked than those of bull ous congenital ichthyosiform erythroderma with relatively mild hyperkeratos is usually limited to the skin flexures. Mutations in the epithelial cytoke ratin 2e (K2e), which is expressed in a differentiation-specific fashion in the upper spinous and granular layers of the epidermis, have been shown to cause IBS. We detected a novel mutation in a three generation kindred with IBS (1448T-->A) within exon 7 of the KRT2E gene. This is predictive of an I483N substitution in the 2B domain of K2e. This extends the range of mutat ions reported to date and illustrates the usefulness of molecular genetics in the diagnosis of this disorder.