Turkish Journal of Gastroenterology, cilt.35, sa.5, ss.374-384, 2024 (SCI-Expanded)
Background/Aims: Peutz-Jeghers syndrome (PJS) is a rare hereditary disorder linked to increased cancer risk due to specific geneticvariants in the STK11 gene. This study aimed to assess disease manifestations, genetic profiles, and genotype-phenotype correlations in PJS patients. Materials and Methods: Twenty patients from 14 families with PJS who were followed up at our clinic between 2011 and 2021 were included. Genetic susceptibility to hereditary cancers was assess-ed using targeted next-generation sequencing (NGS) and multiplex ligation-dependent probe amplification (MLPA) of the STK11 gene. Clinical data were also collected and analyzed in conjunction with the genetic findings. Results: Initial symptoms appeared around 18.9 years, predominantly abdominal pain and intussusception. Mucocutaneous lesions were found in 85%, and hamartomatous polyps in 90%. Dysplastic polyps were found in 4 patients, with 3 cases of malignancy. Nextgeneration sequencing identified 11 pathogenic and 3 likely pathogenic mutations, including 3 novel STK11 variants (LRG_319: c.598- 8_601del, LRG_319: c.708_718del, and LRG_319: c.146_147del). Next-generation sequencing diagnostic rate was 78.5% (11/14), and the overall diagnostic rate with NGS and MLPA studies was 85.7% (12/14). Patients without STK11 mutations had later symptom onset and potentially lower cancer risk. Truncated mutations are associated with earlier symptoms and elevated cancer risk. Conclusion: This is the first PJS case series in Türkiye using the NGS and MLPA methods. It reports 3 novel mutations and emphasizes the genotype-phenotype relationship of PJS. With further studies, the genotype-phenotype relationship of STK11 variants will be better understood.