OBJECTIVETo investigate clinical characteristics and mutation of the LKB1 gene in a Peutz-Jeghers syndrome (PJS) pedigree.

METHODClinical data of a PJS family were analyzed and LKB1 gene mutation was detected by systematic screening with multiplex ligation-dependent probe amplification (MLPA) and DNA sequencing. Meanwhile, two hundred and fifty healthy adults were enrolled in this study and denaturing high performance liquid chromatography (PCR-DHPLC) was carried out to verify the mutation excluding polymorphism sites found in this family. Changes in protein structure and function caused by the mutated coding sequence was analyzed by SWISS-MODEL software.

RESULTThe proband had pigmented mucocutaneous lesions and multiple hamartomatous polyps in the gastrointestinal tract. There was no fragment deletion of LKB1 gene detected by MLPA. Among PJS family and 250 healthy adults, germline mutation c. 924G > C of LKB1 which cause Trp308Cys in protein sequence was identified only in the proband and another affected member. LKB1 protein activity could be reduced due to changes in LKB1 protein conformation structure by Trp308Cys.

CONCLUSIONPeutz-Jeghers syndrome (PJS) is an autosomal dominant disorder characterised by mucocutaneous pigmentation, multiple gastrointestinal hamartomatous polyps and heredofamilial nature. Gene identification and mutagen screening of LKB1 gene in all PJS patients and first degree relatives will contribute to a definite diagnosis and improve the life span of the family.