[The course and clinical manifestations of Peutz-Jeghers syndrome in the Russian population].

BACKGROUND: Peutz-Jeghers syndrome (PJS) is a rare hereditary syndrome characterized by the growth of hamartomatous polyps in the gastrointestinal tract, perioral pigmentation and an increased risk of malignant neoplasms. The syndrome is caused by a pathogenic variant in the STK11 gene. AIM: To assess the clinical picture and treatment of Russian patients with PJS. MATERIALS AND METHODS: A retrospective analysis of 30 patients from 25 families with an established diagnosis of PJS who were in the Ryzikh State Scientific Center for Coloproctology from 2011 to 2021 was carried out. All patients underwent instrumental examination, including esophagogastroduodenoscopy, colonoscopy, X-ray examination of the small intestine/CT-enterography, in the absence of invaginates - video capsule endoscopy, as well as molecular genetic examination for the presence of pathogenic variants in the STK11 gene. All removed polyps were subjected to the histological examination. RESULTS: The analysis of the clinical picture allowed us to establish the following data: the first complaints in patients were noted in childhood and adolescence, while the median age was 11 [7; 19] (0.5-24) years; pathogenic variants in the STK11 gene were identified in 26 (87%) cases, among which 10 were described for the first time; during the initial examination, polyps in the small intestine were detected in all 30 (100%) patients, in the stomach - in 23/30 (77%) patients, and in the colon - in 21/30 (70%); with an age, an increase in the number of polyps in all parts of the gastrointestinal tract was noted; before the diagnosis operations were performed urgently for intestinal obstruction; after the diagnosis of PJS, when polyps were detected in the gastrointestinal tract, endoscopic polypectomies were performed; if endoscopic removal of hamartomatous polyps was impossible, patients were operated as planned; malignant diseases of the predominantly reproductive system were detected in 8/30 (27%) patients. The median age of cancer detection was 52 [31; 52] (17-59) years. CONCLUSION: Russian patients with PJS have population-specific features in the clinical picture of the course of the disease, which dictates the need to develop their own recommendations for monitoring and treatment of such patients.

Identification of large deletions in the APC gene in Russian patients with familial adenomatous polyposis.

Familial adenomatous polyposis (FAP) is a hereditary syndrome characterized by the presence of multiple adenomatous polyps in the colon. The main cause of the disease is a germline mutation in the APC gene. Here we report 4 unrelated FAP patients with different large deletions in the APC gene detected by Multiplex Ligation-dependent Probe Amplification (MLPA) method: deletion of exons 7-15, deletion of promoters B, A, and 5'-UTR region and deletion of promoter B (in 2 patients). The deletion of promoters B, A, and 5'-UTR was not described in the literature earlier, so we report it for the first time. In 2 families with promoter B deletion, we could identify the tendency for decreasing the age of disease manifestation in each next generation, in contrast to the previous one. The incidence of large deletions in APC among Russian patients with FAP reached 4.8% and our finding suggests the need to study this gene by MLPA in "no mutation patients" after Sanger's sequencing.