Introduction. MicroRNAs (miRNAs) are a class of short non-coding RNA molecules that play a central role in the post-transcriptional regulation of gene expression. These molecules are involved in key cellular processes such as proliferation, apoptosis, differentiation, and angiogenesis, making them crucial regulators of cellular homeostasis. Depending on the context, miRNAs can act as oncogenes or tumor suppressors, regulating signaling pathways associated with the development and progression of malignancies, including the PI3K/AKT and Wnt/β-catenin pathways.
Aim: to provide a comprehensive analysis of the role of miRNAs in the pathogenesis and therapy of oncological diseases.
Results. The article explores the potential of miRNAs as biomarkers for early diagnosis, such as miR-21 in pancreatic cancer and miR-141 in prostate cancer. It also highlights findings from preclinical and clinical studies demonstrating the therapeutic potential of miRNAs, including the use of AntagomiR-21 and miR-34a mimics (MRX34). Challenges related to delivery and biosafety are also addressed, with potential solutions proposed through the application of nanotechnology. The molecular mechanisms of their involvement in tumor progression, their diagnostic potential, and therapeutic applications are discussed. Special attention is given to recent advancements, including the use of next-generation sequencing (NGS) for miRNA profiling and CRISPR/Cas9 for functional analysis.
Conclusions. The findings confirm that miRNAs represent a promising direction in the diagnosis and treatment of oncological diseases. Continued research in this field could significantly enhance our understanding of the molecular mechanisms underlying cancer and lead to the development of personalized therapeutic approaches.

Introduction. The global burden of hereditary pathologies (HP) continues to rise, driven by advancements in molecular diagnostics, expanded phenotype characterization (7,586 disorders cataloged in OMIM), and increased accessibility of genetic testing in public healthcare. This study investigates the prevalence and spectrum of HPs in the ethnically diverse population of Mozdok District, Republic of North Ossetia-Alania (RNO-A), to elucidate genetic disease patterns across distinct demographic groups.
Methods. A population-based genetic epidemiological study was conducted among 90,244 individuals in Mozdok District, comprising three primary ethnic groups: Russians (48.95%, n = 44,172), Kumyks (17.87%, n = 16,123), and Ossetians (8.69%, n = 7,841), alongside 13 smaller groups (24.49%, n = 22,108). Utilizing a methodology developed by the Research Centre for Medical Genetics (RCMG), the burden of HPs (per 1,000 individuals) was calculated, and disease diversity was analyzed for autosomal dominant (AD), autosomal recessive (AR), and X-linked disorders. Comparative analyses of prevalence across ethnic groups employed chi-squared tests and Fisher’s exact test. Confirmatory genetic testing (high-throughput sequencing, Sanger sequencing, MLPA) was performed in select cases.
Results. A total of 333 patients (from 241 families) were diagnosed with 107 distinct HPs. The cumulative HP prevalence was 3.79 per 1,000 individuals (1:264), with significant ethnic variation: Kumyks exhibited the highest burden (6.76/1,000; 1:148), followed by Ossetians (4.98/1,000; 1:201) and Russians (2.31/1,000; 1:433). Thirty-three frequent HPs (prevalence ≥1:30,000) accounted for 74.43% of cases (n = 248), including 13 AD, 10 AR, and 10 X-linked disorders. Genetic confirmation was achieved in 74.59% of tested cases (n = 91/122).
Conclusions. This study highlights substantial ethnic disparities in HP prevalence within Mozdok District, ranging from 2.01/1,000 in Russians to 9.49/1,000 in Kumyks. Each ethnic group demonstrated a unique profile of frequent HPs, reflecting founder effects or consanguinity patterns. These findings align with trends observed in other multi-ethnic populations and underscore the

Introduction. Beta-thalassemia is one of the most common inherited disorders characterized by reduced or complete absence of beta-globin chain synthesis. The CBC parameters of patients with beta-thalassemia are often similar to other microcytic hypochromic anemias, which makes it difficult to use these parameters for the purpose of differential diagnosis of anemias. The prevalence of beta-thalassemia is increasing in non-endemic regions, including the Russian Federation. However, in our country, the prevalence, laboratory and molecular genetic features of beta-thalassemia remain insufficiently studied.
Objective: to characterize hematological and molecular genetic features of beta-thalassemia in laboratory practice.
Methods. The present study examined the results of CBC of 58266 patients over 18 years of age. Patients with hemoglobin and/or mean corpuscular volume and/or mean corpuscular hemoglobin values below the reference values were selected according to the results of a complete blood count. Mentzer and Sirdah’s calculated indices were utilised for further differentiation. Patients with both indices below the threshold values were subjected to direct automatic Sanger sequencing of the HBB gene.
Results. Among 58266 patients, 20040 (34.39%) had Hb and/or MCV and/or MCH values below reference values. Values of both calculated indices indicated beta-thalassemia in 182 patients (0.91% among patients with CBC changes, 0.31% among all subjects). Using the Sanger direct automatic sequencing method, pathogenic variants of the HBB gene were identified in 64 patients, which is 0.32% among patients with CBC changes or 0.109% among all examined individuals. The most common pathogenic variant of the HBB gene in this study is c.25_26del (rs35497102) (21.8%).
Conclusions. A total of 20 different pathogenic variants located in all regions of the HBB gene were detected in this study, which underlines the necessity of studying the nucleotide sequence of the entire gene in the diagnosis of beta-thalassemia using molecular genetic methods. The findings of this study demonstrate that the utilisation of CBC and calculated erythrocyte indices possesses the capacity to categorise patients into distinct risk groups; nevertheless, these methodologies are not characterised by a high degree of sensitivity. The development of more effective methods of differential diagnosis of beta-thalassemia from other microcytic hypochromic anemias is necessary.

Introduction. Genes involved in pathogen-host interactions, as well as those providing dietary adaptation, are most subject to natural selection. The fucosyltransferase 2 gene FUT2 is responsible for selective selection of microorganisms and maintaining the stability of the gastrointestinal microbiome in humans. Regulation of fucosylation associated with FUT2 gene polymorphism makes carriers of different alleles resistant or, on the contrary, susceptible to certain infectious and associated diseases. Interpopulation differences in the frequency of the nonfunctional allele -772A are known; however, studies among Siberian ethnic groups remain relevant.
Aim: to identify ethnic peculiarities in the distribution of variants of the clinically relevant FUT2 gene in Siberian populations.
Methods. The material for the study was DNA samples of representatives of four ethnic groups: Yakuts of Beidinge and Dyupsya settlements of Ust-Aldan ulus of the Republic of Sakha (Yakutia) (N=123), Tuvinians of Kyzyl city of the Republic of Tyva (N=308), Kazakhs of Zhana-Aul settlement, Kosh-Agach district of the Republic of Altai (N=155), Russians of Siberia (N=153). Genotyping was performed by standard real-time PCR method.
Results. The frequency of the non-secretory allele ‒772A of FUT2 was minimal in the Yakut sample (7.3%), statistically significantly higher in Tuvinians (13.1%). Kazakhs have a significantly increased (29%), compared to these samples, frequency of the studied variant, close to that of the Russian group (34%).
Conclusions. Consistent with the general geographic gradient of polymorphic variant distribution, allele frequencies of the FUT2 gene (G772A, rs602662) in samples of Yakuts, Tuvinians and Kazakhs in Altai occupy an intermediate position between Caucasoids and East Asian populations. This indicates, probably, different selective pressures in different geographical areas, determined by both local pathogens and traditional diet.

Apolipoprotein E is involved in lipid metabolism and many other important processes in the body. Polymorphism in the APOΕ gene has a huge impact on the risk of developing and severity of such serious diseases as Alzheimer’s disease, type III hyperproteinemia, cardiovascular, oncological and many others. Therefore, the importance of studying this polymorphism in human populations is undoubted. This paper presents the frequency of occurrence of APOΕ genotypes and its polymorphic variants ε2, ε3, ε4 in 8 populations of indigenous peoples living in Eastern and Southern Siberia (Yakuts, Buryats, Teleuts, Dolgans, Nganasans, Russians). Inter-population comparisons have been made between the populations studied by us and some of the world’s populations.