In adipose tissue (AT), microRNAs play an important role in the regulation of biological processes such as adipogenesis, lipid and glucose transport, insulin sensitivity, and inflammation. Therefore, changes in the microRNAs expression profile of AT may be associated with the development of obesity concomitant pathologies. The aim of this work was to evaluate the level of hsa-miR-551b-3p, hsa-miR-145-5p, has-miR-132-3p, hsa-miR-10a-5p, hsa-miR-302d-3p, hsa-miR -1246, hsa-miR-210, hsa-miR-155-5p, hsa-miR-181a in subcutaneous and visceral AT (SAT and VAT) in obese patients with/without type 2 diabetes mellitus (T2DM). Our study demonstrated that the relative expression level of the microRNA hsa-miR-132-3p was reduced in the SAT of obese patients with T2DM compared with obese patients without T2DM and controls. In the subgroup of patients with obesity and T2DM, the level of hsa-miR-132-3p expression in AT was positively correlated with the concentration of glucose (r=0.465, p=0.045 – for SAT; r=0.563, p=0.006 – for VAT) and glycated hemoglobin in blood plasma (r=0.593, p=0.005 – for VAT). In obese patients (with/without T2DM), inverse correlations were observed between the level of has-miR-551b-3p expression in SAT and glucose metabolism parameters: insulin (r=-0.409, p=0.020), C-peptide (r=-0.360, p=0.043), index HOMA-IR (r=-0.540, р=0.002). Thus, it can be assumed that the microRNAs hsa-miR-132-3p and hsa-miR-551b-3p in adipose tissue are involved in the development of insulin resistance and T2DM in obese individuals.

Introduction. The study of early human embryogenesis involves the analysis of a limited amount of biological material. Most methodological approaches do not allow for the simultaneous analysis of several blastocyst characteristics on the same material. This paper presents the results of a pilot study on RNA sequencing of the inner cell mass (ICM) and trophectoderm (TE) cells of human blastocysts.

Aim: evaluation of the feasibility of gene expression analysis and blastocyst karyotype reconstruction using whole transcriptome sequencing data.

Methods. Material – 16 human blastocysts, which were obtained as part of in vitro fertilization (IVF) cycles at the Regional Perinatal Center named after I.D. Yevtushenko. Blastocysts were mechanically divided into the ICM (2 fragments) and TE (3 fragments). Sample preparation of libraries for RNA sequencing was carried out using the commercial QIAseq FX Single Cell RNA Library Kit (Qiagen, Germany). Sequencing was performed using a NextSeq 550 instrument and commercial NextSeq 500/550 High Output Kit v2.5 sequencing kit and NextSeq 500/550 High Output Kit v2 kit (Illumina, USA), as well as a NextSeq 2000 instrument (Illumina, USA) and a commercial NextSeq 2000 P3 reagents (300 cycles) kit (Illumina, USA). Bioinformatics data processing was performed using FastQC, multiQC, STAR. RStudio. superFreq. Embryoid bodies (EBs) obtained from induced pluripotent stem cell (iPSC) lines were used as reference samples with confirmed normal karyotype to reconstruct molecular karyotypes of the studied samples.

Results. In blastocysts on day 7 of development, in comparison with blastocysts on day 5 (7vs5), a group of genes responsible for blastocyst growth (CTR9, GINS1 and ZNF830) was identified. When comparing 7vs5 and 6vs5, several groups of genes responsible for protein localization and translation were identified. A total of 286 signs of chromosomal instability (CIN) were identified. Amplifications, deletions, partial amplifications and deletions of autosomes occurred with a frequency of 48.3%, 34.3%, 11.2% and 6.3%, respectively. The most frequently detected copy number abnormalities were chromosomes 3, 5, 9, 10, 12, 15, 16, 17, 19, 22. We found an inverse statistically significant correlation between the quality of TE and the number of CIN in the ICM, as well as a tendency to decrease CIN in the trophectoderm with a change in the quality of TE from “C” to “A”.

Conclusions. Reconstruction of blastocyst karyotypes based on whole-transcriptome analysis data is possible and is of interest from the point of view of studying the relationship between the expression profiles of blastocyst cells and their chromosomal constitution.

Background. Retinitis pigmentosa is a group of inherited degenerative retinal diseases resulting from the progressive death of cells of the pigment epithelium, photoreceptor cells - rods and then cones, which leads to gradual loss of vision.

Aim: to study the clinical polymorphism and genetic heterogeneity of isolated and syndromal forms of retinitis pigmentosa in closed isolates of the Republic of Buryatia.

Methods. The sample included 74 patients with a preliminary diagnosis of isolated retinitis pigmentosa or syndromal retinitis pigmentosa (Usher syndrome) according to the data of routine methods of research, living in closed isolates of the Republic of Buryatia. This report describes the structure of hereditary retinal pigment dystrophies in closed isolates of the Republic of Buryatia based on the data of clinical, instrumental (optical coherence tomography, electroretinography) and molecular genetic diagnostic methods (NGS, Sanger sequencing, MLPA).

Results. Among the examined group of population mutations were found in 13 genes with the highest frequency of mutations in USH2A (58,8%) and CHM (23,5%), NR2E3(17,6%) genes, with equal frequency of 11,8% in GUCY2D, SNRNP200, TULP1, CEP290 genes. ABCA4, GRK1, MY07A, PDE6A, RP1L1, TTC21B mutations were identified in one case (5.9%). In 64.7% of the identified mutations were pathogenic, in 17.6% were probably pathogenic and in another 17.6% were mutations with unknown clinical significance with possible relevance to the phenotype. Analyzing the quantitative distribution of patients according to certain types of inheritance, it was found that 83.4% of patients had autosomal recessive disease, 8.3% had autosomal dominant disease, and 8.3% had X-linked recessive disease. Changes in USH2A (Usherin) gene were verified in the majority of cases, in 10 out of 17 people who gave their consent for molecular genetic study, which, in its turn, allowed to establish the clinical and genetic diagnosis of Usher syndrome type 2A in 6 probands, isolated retinitis pigmentosa type 39 in 4 probands, including 3 patients with classic course of PR, 1 - with pigmentless form.

Conclusion. An interdisciplinary survey taking into account the data of clinical-instrumental and molecular genetic diagnostics allowed us to study the clinical polymorphism of a genetically heterogeneous group of retinal diseases among the Old Believers living in the territory of the Republic of Buryatia.

Background. The healthcare has the priority importance for the Northern Eurasia indigenous populations survival. The organism viability largely depends on the availability of effective protective systems against adverse factors. The one is 8-oxoguanine DNA glycosylase (OGG1) which help to resist against the adverse effects of oxidative stress.

The human OGG1 gene has coding sequence variations which may differ in different ethnic groups. The Ser326Cys mutation reduces the effectiveness of the DNA repair function and it causes an increased risk of carcinogenesis and some other adverse health consequences.

Objective: to estimate the prevalence OGG1 gene variants among the indigenous Khants population and to compare it with different ethnic groups worldwide.

Methods. The sample of Eastern Khants consisted of 103 indigenous inhabitants of the Khanty-Mansiysk Autonomous Okrug. OGG1 gene Ser326Cys polymorphism genotyping (rs1052133) was performed using the ARMS-PCR-RFLP method.

Results. The frequency stated for Ser/Ser genotype was 47.6%, Ser/Cys = 36.9 % and Cys/Cys = 15.5% in the Khants population. Frequency of the OGG1 allele*C (Ser) was equal to 0.66, and OGG1*G (Cys) reached the value of 0.34. .

Conclusion. The results of the study provide new population-genetic information on the prevalence of variants of the OGG1 gene. The frequencies of the rs1052133 alleles in the Khants population were close to the global average values.

Kidney stone disease (KSD) is a common disease of the urinary system. It is important to determine the risk of transmitting the disease to the next generation for the patients suffering from the severe forms of urolithiasis. At the same time, an important aspect is to prepare a woman with KSD for the pregnancy. In the current article we describe a case of genetic counseling of a 37-year-old patient with cystinuria and infertility problem who came for consultation because of pregnancy planning. The woman and her husband underwent comprehensive laboratory and instrumental investigation together with molecular genetic analyses. Genetic diagnostics were carried out using the next generation sequencing method (NGS, from the English Next Generation Sequencing) with subsequent verification of the detected findings using the Sanger sequencing method. Before genetic counseling the couple had already undergone several genetic tests: karyotyping of both spouses (results 46,XX and 46,XY) and genetic testing of the woman for the presence of polymorphisms in the F2 and F5 genes, predisposing to the development of thrombophilia. As a result of genotyping, the patient was determined to have the rs1799963 polymorphism of the F2gene in a heterozygous state. During the consultation, to identify the genetic cause of cystinuria, the patient was prescribed whole exome sequencing. In the SLC7A9 gene, attributable for the development of cystinuria type B, a pathogenic variant c.313G>A (p.Gly105Arg) was identified in a homozygous form. The diagnosis of rare form of KSD was confirmed. In addition, the woman also had other findings associated with a number of hereditary diseases (genes ABCA4, GPR179, C2, GALC). Based on the results of exome sequencing of the patient’s husband, no matches were found for variants in the same genes of autosomal recessive diseases. Personalized recommendations were given for preparing and managing pregnancy, as well as preventing the development of complications of health condition in the future. Treatment of cystinuria was prescribed to the woman. The importance of medical genetic counseling is shown when planning childbearing in a patient with a rare form of KSD, who is additionally a heterozygous carrier of pathogenic variants in the genes of a number of monogenic diseases and genetically predisposed to thrombosis.

Background. Epigenetic processes such as DNA methylation play an important role in maintaining a normal pregnancy and their disruption may be associated with spontaneous abortion. Earlier, we found an increased level of methylation of the retrotransposon LINE-1, which makes up about 17% of the human genome, in the chorionic villi of spontaneous abortions.

Aim: to analyze the level of methylation of the LINE-1 retrotransposon in chorionic villi in embryos from families with sporadic and recurrent miscarriage.

Methods. The present study analyzes the differences in the level of methylation in chorionic villi of 46 induced abortions and spontaneous abortions from 155 families with sporadic miscarriage and 127 families with recurrent miscarriage. The methylation level of LINE-1 was assessed using targeted bisulfite massive parallel sequencing.

Results. No significant differences in LINE-1 methylation levels were found between the groups with recurrent and sporadic miscarriage (p>0.05). However, the LINE-1 methylation level was significantly higher compared to induced abortions (40.2 ± 2.2%) in spontaneous abortions with monosomy X from families with recurrent (42.0 ± 4.5%, p=0.04) and sporadic miscarriage (43.1 ± 5.2%, p=0.03), and in spontaneous abortions with trisomy 16 from families with sporadic miscarriage (43.1 ± 3.9%, p<0.001).

Conclusion. Abnormal methylation level of LINE-1 may be a marker of the death of part of the embryos in both sporadic and recurrent miscarriage.

A reduction in the indices of T- and B-lymphocytes is a common feature of a number of pathological conditions. The assessment of these indices is of paramount importance in the context of newborns, as the absence of timely diagnosis and treatment can result in the development of severe infectious diseases, disability, and high mortality. The objective of this study was to develop a highly sensitive and precise method for enumerating naïve T- and B-lymphocytes based on the quantification of excision circular DNA molecules TREC and KREC through digital polymerase chain reaction. Consequently, a specific set of primers and probes was developed, enabling highly accurate determination of the number of TREC and KREC molecules and counting of the number of nucleated cells. The proposed method exhibits high diagnostic specificity and sensitivity, rendering it suitable for use in both screening diagnostics of immunodeficiency states in newborns and for assessing the immune status in adults with various immunopathological conditions.