Clinical characteristics and LKB1/STK11 gene mutation in a family of Peutz-Jeghers syndrome

Objective To investigate the effects of LKB1/STK11 gene mutation and methylation in Peutz-Jeghers syndrome (PJS) , and to analyze the relationship between the types of gene mutation and clinical characteristics. Methods The peripheral blood of 4 affected members and the intestinal polyp tissue of the proband a family of PJS were collected in the Department of Chemotherapy, Jiangsu Provincial Cancer Hospital. The DNA from the corresponding tissues was extracted. The large deletion, base mutation, base insertion and deletion in the LKB1/STK11 gene originated from the germline and somatic cells were determined by MLPA and PCR-DNA sequencing, respectively. The gene promoter methylation in the cancerous polyp tissue of the proband was determined by MSP. Results The proband and the affected family members had typical clinical manifestations of PJS: the hamartomatous polyps in the digestive tract (all pathological specimens were verified by colonoscopy in different hospitals) and pigmentation at the mucosa. Large deletionof the DNA mutation were found in the peripheral blood and colorectal polyps of the proband and the affected family members, which suggested pathological significance. Methylation of the LKB1/STK11 gene was determined in the cancerous polyp tissue of the proband. Conclusion The detection of LKB1/STK11 gene mutation in the PJS family can be used as an effective method to predict the risk. There is a close relationship between the type and location of gene mutation and clinical symptoms. The change of methylationstatus may be an important mechanism of hereditary PJS polyps. Key words: Peutz-Jeghers syndrome; Mutation; Methylation; LKB1/STK11 gene