Mutation Analysis of STK11/LKB1 Gene in Patients with Peutz-Jeghers Syndrome in Taiwan: A Preliminary Report

Purpose: Peutz-Jeghers syndrome is an autosomal dominant disorder characterized by hamartomatous polyps in the gastrointestinal tract and pigmented macules of the lips, buccal mucosa, and digits. It was shown that germline mutations of the STK11/LKB1 gene are responsible for Peutz-Jeghers syndrome. The STK11/LKB1 gene is predicted to encode a serine/threonine kinase and might be a tumor-suppressor gene. We investigated the role of the STK11/LKB1 gene in patients with Peutz-Jeghers syndrome in Taiwan. Methods: Mutation analysis of genomic DNA was performed on one familial case (comprising three family members) and three sporadic cases with Peutz-Jeghers syndrome. All nine exons of the STK11/LKB1 gene and the flanking intron boundaries were amplified, followed by direct sequencing. Direct sequencing in each family and in normal controls further verified the mutations. Results: Mutations in the functional domains of the STK11/LKB1 gene were identified in one sporadic case only (4016G＞A, R297K), which was reported twice previously. In addition, we detected three polymorphisms in the STK11/LKB1 gene. Conclusions: We reported a mutation of the STK11/LKB1 gene in one sporadic case of Peutz-Jeghers syndrome. In the remaining one familial (three patients) and two sporadic Peutz-Jeghers syndrome cases, we found no apparent abnormalities of the STK11/LKB1gene, which could reflect the existence of locus heterogeneity in Peutz-Jeghers syndrome.