Mutation Of STK11 Gene In A Family With Peutz-Jeghers Syndrome

Mutation of STK11 gene in a family with Peutz-Jeghers syndromeBackground Peutz-Jeghers syndrome(PJS) is a rare,autosomal dominant inherited disorder characterized by the presence of melanin spots on the lips,buccal mucosa, terminal digits and multiple gastrointestinal hamartomatous polyps.The incidence has been estimated as one in 200 000 births.The onset age of the disease is usually during early childhood.The patients are at an increased risk of benign and malignant neoplasms of the gastrointestinal tract,the pancreas,ovaries,testes,breast,lungs,and uterus.Overall,the median age of cancer diagnosis is around 50 yr.In 1997,a candidate gene locus for PJS was mapped to chromosome 19p13.3 by a strategy combining comparative genomic hybridization and loss of heterozygosity(LOH) analysis of PJS polyps with genetic linkage studies.Subsequently,a PJS candidate gene STK11(LKB1),was.cloned by two different groups.The gene encodes for a novel 433-aminoacid serine threonine kinase with strong sequence similarity to the cytoplasmic serine threonine kinase XEEK1 of Xenopus laevis.STK11 may function in cells as a tumor suppressor.Identification of truncating germline mutations of STK11 further implicated this gene in PJS.To date,172 different mutations in the STK11 gene have been reported and most of them result in a truncated,inactive protein.Objective To identify the mutation of STK11 gene in a Chinese family with Peutz-Jeghers syndrome.Methods We collected one Chinese familial PJS patients and their blood samples. Genomic DNA was extracted from peripheral blood.All the coding exons of STK11 gene of the patients and 100 unrelated population-matched controls were amplified by polymerase chain reaction and followed by direct sequencing.Results we identified a missense mutation c.725G＞A(p.G242E) in the patients,but normal in all controls.The mutation of STK11 gene have been reported abroad,which was first reported in China. Conclusions The c.725G＞A(p.G242E) missense mutation of STK11 gene is the cause of clinical phenotype of the patients in this Chinese family with Peutz-Jeghers syndrome.