EPIDERMOLYTIC PALMOPLANTAR KERATODERMA COSEGREGATES WITH A KERATIN-9 MUTATION IN A PEDIGREE WITH BREAST AND OVARIAN-CANCER

Epidermolytic palmoplantar keratosis (EPPK) cosegregates with breast a nd ovarian cancers in a large French pedigree, raising the possibility that a single genetic mutation might cause these conditions and offer ing a potential lead to the identification of a hereditary breast/ovar ian cancer gene. We have performed linkage analysis and show that the EPPK locus lies on the long arm of chromosome 17 near the type I kerat in gene cluster and the proposed breast cancer gene (BRCA1). The type I keratin 9 gene has been partially sequenced in four affected individ uals. A single base mutation within the rod domain of the protein cose gregates with EPPK in all affected individuals tested. Although inheri tance of this mutation is likely responsible for EPPK, it is unlikely to be the cause of the breast and ovarian cancer.