The current version of the International Human Cytogenomic Nomenclature System (ISCN 2020) is published in 2020. This review reflects all the important changes from the previous 2016 version of the nomenclature, which may be relevant for recording the results of a standard cytogenetic study. First of all, it concerns the order of recording chromosome breakpoints and marking the inheritance of rearrangements in the conclusion of the study results. The new version also adds some sections and tables, modifies and adds examples of recording the karyotype formula at various rearrangements, and makes changes in the text structure.

An International System for Human Cytogenomic Nomenclature has been and remains a single universal language ofcytogenetics all over the world. The unification of terms, abbreviations and formulas for describing chromosomal abnormalities, along with an understanding of the mechanisms that lead to the formation of these rearrangements, is the basis of the current International Cytogenomic Nomenclature System (ISCN). The rapid development in the field of molecular genetic technologies in recent decades forces authors to periodically update the nomenclature and supplement it with new data. A comparative analysis of ISCN 2020 and the previous version of the ISCN 2016 allowed us to demonstrate the main changes in the record of cytogenomic study results and conclude that the additions in the nomenclature reflect the current approach to the diagnosis of chromosomal abnormalities.

Background. Gene polymorphism of the xenobiotic detoxification system is associated with drug resistance and human diseases such as cancer, Parkinson’s disease, Alzheimer’s disease, atherosclerosis, liver cirrhosis, aging, cataract formation, infertility, insomnia. Frequency of the polymorphic variants of GSTs genes varies in different world populations.

The purpose of this study is to characterize the frequency distribution of genotypes of the GSTM1, GSTT1 genes, as well as genotypes and alleles of the Ile105Val, Ala114Val polymorphic variants of the GSTP1 gene in the populations of the Russians and the Buryats living in Eastern Siberia and to establish the ethnic differences in the frequency characteristics of the studied genes.

Methods. The sample included 461 people, including 264 Russians and 197 Buryats. Molecular genetic study of deletion polymorphism of GSTT1 and GSTM1 genes was carried out using the polymerase chain reaction (PCR) method with electrophoretic detection. The Ile105Val (rs1695) and Ala114Val (rs1138272) polymorphism of the GSTP1 gene was studied using the real-time polymerase chain reaction (Real-Time PCR) method.

Results. Comparative analysis of the frequency distribution of genotypes of the GSTM1 and GSTT1 genes did not reveal statistically significant differences between the compared population samples. The frequency of the deletion genotype of the GSTM1 gene in the populations of Russians and Buryats was 44.7 and 48.7%, of the GSTT1 gene 22.4 and 30.5%, respectively. It was shown that there are statistically significant differences in the frequency distribution of genotypes of polymorphic variants Ile105Val (p=0.023) and Ala114Val (p=0.007) of the GSTP1 gene between the compared population samples. The frequency of the rare alleles in the populations of Russians and Buryats was as follows: allele G (Ile 105Val) - 23.67 and 20.56%, allele T (Ala 114 Val) - 10.23 and 4.57% (p=0.002), respectively.

Conclusions. The compared population samples of the Russians and the Buryats do not differ in the frequency of deletion genotypes of the GSTM1, GSTT1 genes. At the same time, significant differences in the frequency distribution of genotypes of the Ile105Val, Ala114Val polymorphic variants of the GSTP1 gene are observed in the compared groups. Comparison of the data obtained in this study with similar data in other world populations showed that the frequency characteristics of GSTs genes in the studied populations of the Russians and the Buryats are within the frequency of these genes in other European and Asian populations.

We conducted this meta-analysis to estimate associations between polymorphisms of ANRIL rs2383207 and susceptibility to atherosclerosis. A systematic literature research of Google Scholar and PubMed was performed to identify eligible studies. Overall, 12 studies were included for meta-analyses. The association was assessed by statistical odds ratio (OR) with 95% confidence interval (CI). RevMan software (Cochrane Collaboration, 5.3. Copenhagen) was used for the meta-analysis. Pooled overall analyses showed that ANRIL was associated with risk of atherosclerosis in the whole population. Further analyses by ethnicity revealed that ANRIL was associated with susceptibility to atherosclerosis in Asians and Caucasions. Our results suggest that ANRIL, might serve as genetic biomarkers of atherosclerosis. Further studies will be required to confirm the observed association.

Inborn errors of metabolism are an extensive group of congenital diseases, collectively affecting up to 2-3 % of the population. Anumber of hereditary metabolic diseases is characterised by an acute and earlier beginning in the first days or months of a child’s life and anaggressive course with a high probability of mortality. This course of the disease requires a rapid development of a strategy for the examination and treatment of the patient. The article presents a clinical example of a child with maple syrup urine disease. Given the rare frequency, it is very difficult to collect and analyze a large group of patients with leucinosis. Therefore, the description of even a single case is of clinical interest and is useful for highlighting the medical audience.

Balanced chromosomal rearrangements increase the risk of gametogenesis defects, infertility, aneuploidy rate and reproductive losses. The frequency of Robertsonian translocations (rob) in men with infertility, especially with severe forms of impaired spermatogenesis, is higher than in the general population, but there is lack of understanding of mechanisms of gametogenesis disorders in rob carriers. Purpose: to evaluate gametogenesis in male rob(14;15) carriers.   Two infertile male rob(14;15) carriers were examined. Semen analysis and quantitative karyological analysis of immature germ cells of the ejaculate were performed.  Oligoasthenoteratozoospermia caused by incomplete spermatogenic arrest at the prophase I of meiosis was diagnosed in both patients.   Infertility in two examined rob(14;15) male carriers is associated with incomplete meiotic arrest resulting in decreased gamete production.