As PTEN is a dual phosphatase mutated in autosomal inherited disorders with phenotypes similar to those of PJS (Bannayan-Riley-Ruvalcaba syndrome and Cowden disease), our study suggests a functional link between the proteins involved in different hamartomatous polyposis syndromes and emphasizes the central role played by LKB1 as a tumor suppressor in the small intestine.
In this report we present a series of Australian PJS cases, which suggest that mutations in the STK11 gene do not account for many families or patients without a family history.
In the remaining seven PJS families, we found no apparent abnormalities of the LKB1/STK1I gene, which could reflect the existence of locus heterogeneity in PJS.
We investigated the entire coding region of STK11 in 15 unrelated PJS families by the PCR-SSCP (polymerase chain reaction-single strand conformation polymorphism) method and PCR-direct sequence analysis, and found nine different, novel mutations among ten of those families.
In this study, we screened for LKB1 mutations in nine PJS families of American, Spanish, Portuguese, French, Turkish, and Indian origin and detected seven novel mutations.