Genetic and phenotypic characteristics of 60 Russian families with Lynch syndrome

Abstract

AIM: to evaluate the genetic and clinical characteristics of Russian patients with Lynch syndrome.PATIENTS AND METHODS: in the period from 2012 to 2019, patients with suspected Lynch syndrome were studied, according to the selection recommendations (Amsterdam II and original criteria). All patients underwent a microsatellite instability test in the tumor, and if it was detected, for germline mutations in the genes of MMR system. All patients underwent standard clinical procedures (colonoscopy, gastroscopy, CT, MRI, etc.).RESULTS: Lynch syndrome was genetically confirmed in 60 unrelated patients (included 30 women and 30 men, ranging in age from 24 to 68 years). Germline mutations were found in the following genes: MLH1 — 30, MSH2 — 26, MSH6 — 2, PMS1 — 1, PMS2 — 1. For the first time in the world, 12 novel mutations have been described. Clinical features of Russian patients with Lynch syndrome include: the early average age of development of the first cancer — 39.0 years; frequent 45% localization in the left colon; high (55%) incidence of poorly differentiated adenocarcinomas. A total of 234 tumors were diagnosed in Russian patients with Lynch syndrome and their relatives. It is also important to note that the stomach cancer is the third most common cancer after colon cancer.CONCLUSION: Russian patients with Lynch syndrome showed clinical and genetic and features, that distinguish them from European and North American population and should be taken into account when treating.