A novel missense mutation of the STK11 gene in a Chinese family with Peutz-Jeghers syndrome

BACKGROUND: Peutz-Jeghers syndrome (PJS) is a rare autosomal dominant inherited disease caused by mutations in the Serine-Threonine Kinase 11 (STK11) gene. This study aimed to diagnose a Chinese pedigree with PJS and to expand the spectrum of STK11 variants. METHODS: We performed an inductive analysis of clinical features, gastrointestinal endoscopy, radiologic imaging, and pathological findings in a Chinese family with PJS. Whole-exome sequencing (WES), Sanger sequencing, and STK11 protein 3D structure prediction were performed for establishing a molecular diagnosis. RESULTS: The proband, her mother, and grandfather presented with pigmentation spots on lips, oral mucosa, and fingers. Her mother and grandfather also had pigmentation spots on face and feet, while her brother had pigmentation spots only on the lower lip. On endoscopy, polyps were discovered in the proband, her mother, and grandfather. A novel heterozygous mutation (c.521A > C) in exon 4 of STK11 was identified in all four patients, leading to a change from histidine to proline in amino acid 174. The variable site p.H174 was highly conserved in different species on multiple sequence alignment analysis. CONCLUSIONS: We diagnosed a Chinese pedigree with PJS based on clinical features, gastrointestinal endoscopy, and genetic testing results. Our results expanded the spectrum of STK11 variants, which will be helpful for genetic counseling.