STK11/LKB1 germline mutations are not identified in most Peutz-Jeghers syndrome patients

Germline mutations of the STK11 gene mapped to chromosome 19p13.3 are respo nsible for Peutz-Jeghers syndrome (PJS), a dominant disorder associated wit h characteristic gastrointestinal hamartomatous polyps and a predisposition to various cancers. We conducted a detailed investigation of germline STK1 1 alterations by protein truncation test and genomic DNA sequence analysis in ten unrelated PJS families. We identified a novel truncating deletion sp anning STK11 exons 2-7 in a single patient and several known polymorphisms. Loss of heterozygosity studies in PJS polyps of four of these patients ide ntified an allelic deletion of D19S886 in another patient. Our results sugg est that STK11 mutations account for only a proportion of PJS cases.