Among the populations of Eastern Siberia, the Russian old-settlers of the village of Russkoe Ustye (Allaikhovsky district of Yakutia) occupy a special place: their origin is relations with people from the old possessions of Novgorod the Great (presumably around 1570). The investigation of the hypotheses of the origin of the people of Russkoe Ustye, are of considerable scientific interest for the study of the colonization process of Northern Eurasia. In this study analysis of the carrier frequency of the six mutations responsible for autosomal-recessive diseases in 30 unrelated individuals from the village of Russkoye Ustye was performed. In the population of the Russkoe Ustye we did not find any heterozygous mutations, which are the cause of phenylketonuria (0/30), Wilson disease (0/30), congenital cataract (0/30), progressive deafness (0/30), and methemoglobinemia (0/30). In this Siberian population with a carrier frequency of 6.7%, the c.35delG mutation of the GJB2 gene (2/30) responsible for autosomal recessive deafness 1 A was detected. The absence of local East-Siberian variants of founder mutations associated with congenital cataract, progressive deafness, and methemoglobinemia, which are prevalent among Turkic-speaking Yakuts, indicates that this Turkic component in population of Russkoe Ustye is absent or represented to a small extent. Increasingly, than the Turkic component in the in population of Russkoe Ustye is represented a common West-Eurasian component, as indicated by the presence of the c.35delG mutation of the GJB2 gene, which is common in Europe. 

The main cause of congenital or juvenile cataract with autosomal recessive inheritance in Yakutia is the c.1621C>T p.(Gln541*) nonsense mutation in the exon 8 of the FYCO1 gene. Previous studies have shown that the c.1621C>T p.(Gln541*) mutation has spread to the territory of Yakutia as a result of the founder effect. The initial assessment of the average “age” of the mutation using the data of linkage disequilibrium for three STR markers: D3S3685, D3S3582 and D3S3561 showed a result of ~10.4 ± 2.6 generations (260 ± 65.0 years). In the present study, we used a different approach to determine the “age” of the c.1621C>T p.(Gln541*) mutation using the DMLE+ 2.3 software based on the analysis of 25 SNP markers. The calculated DMLE+ 2.3 “age” of the mutation, taking into account the 95% confidence interval, varies from 25 to 67 generations (from 625 to 1675 years). Comprehensive data show that the c.1621C>T p.(Gln541*) mutation could have occurred between the 4th and 18th centuries with the most likely time of expansion from 11th century.

The aim of the research: to analyze the frequency of occurrence of polymorphisms rs8105790 of the IFNL3 gene, rs368234815 of the IFNL4 gene, rs1831583 of the IFNA1 gene in healthy people and patients with chronic viral hepatitis D among the ethnic group of Yakuts living on the territory of the Republic of Sakha (Yakutia).

Materials and methods of the study: to study gene polymorphisms in 157 individuals with chronic HDV infection and 160 apparently healthy individuals was used polymerase chain reaction (PCR). Analysis of the results included compliance with the Hardy-Weinberg law, Pearson's chisquared test (χ2), odds ratio and its confidence interval.

Results: the people of young working age suffer more from HDV infection, wherein the development of cirrhosis from the moment of infection with the D virus is formed on average over 6.5 years. The high replicative activity of the HDV virus in 74.1% of cases is accompanied by suppression of HBV, but with an increase in the severity of fibrosis and the formation of cirrhosis and liver cancer, there is observed simultaneous replication of hepatitis B and D viruses. According to the data obtained, the risk of developing severe fibrosis in HDV is 1.7 times higher in carriers of the ΔG-allele of the rs368234815 polymorphism of the IFNL4 gene (OR=1.784; 95% CI 0.642–4.959) and 1.8 times higher in the carriers of the C-allele of the rs1831583 polymorphism of the IFNA1 gene (OR= 1.818; 95% CI 0.340–9.713).

Conclusion: the obtained results demonstrate that the C-allele rs1831583 of the IFNA1 gene and the ΔG-allele rs368234815 of the IFNL4 gene predispose to the formation of severe fibrosis in HDV infection, Yakutia. Keywords: chronic hepatitis, liver cirrhosis, gene polymorphism, HDV, IFNL3, IFNL4, IFNA1.

Genetic predisposition to obesity may play an important role in its etiology along with environmental influences. One of such potential therapeutic targets is uncoupling protein 3 (UCP3), is encoded by the UCP3 gene. The main functions of UCP3 are considered to be proton transport in the presence of fatty acids, and a protective function, UCP3 can inhibit the actions of reactive oxygen species in mitochondria. The purpose of this study is to search for the association of polymorphism rs1800849 of the UCP3 gene with body mass index (BMI) in the Yakut population. No significant differences in the distribution of alleles were found (χ2 = 0.72; p = 0.397), so the frequency of allele (T) was 53%, and allele (C) was 47%. In females from the control group, it was founding that the heterozygous genotype was more common (p = 0.04) than in people with underweight. In males with overweight, the allele (C) is more common (p = 0.001), compared with the control group. The distribution of alleles of the rs1800849 polymorphism of the UCP3 gene showed that in individuals with underweight (both females and males), the frequency of the allele (T) was significantly higher than the frequency of the allele (C) (p = 0.001). Allele (C) was more common in overweight males (p = 0.001), no such differences were found in females (p > 0.05). The article discusses the probable relationship of the distribution of rs1800849 alleles of the UCP3 gene with the rate of basal metabolism affecting body weight, which is probably due to adaptation to a cold climate.

Alport syndrome is a hereditary progressive kidney disease associated with sensorineural hearing loss and vision abnormalities, which is caused by mutations in the COL4A3, COL4A4, and COL4A5 genes encoding the α3, α4, and α5 type IV collagen chains. This paper presents a case with a novel hemizygous mutation in the COL4A5 gene in a Yakut family with Alport syndrome. The study involved 228 GJB2-negative patients with varying degrees of hearing loss and deafness living in the Republic of Sakha (Yakutia). Brothers were selected from this sample with a history of similar hearing and kidney impairments. For one of the sibs, a complete exome sequencing was performed, which resulted in the discovery of a new hemizygous mutation c.2375delA p.(Asp792fs) in exon 29 of the COL4A5 gene on the long arm of the X chromosome (Xq22). This mutation was also detected in sibling using PCR-RFLP analysis

Changes in the endometrial microbiome (dysbiotic type) were more often combined with dyschronism phenomena (inconsistency in the rate of the gland maturation with the secretory phase of the menstrual cycle) in women than with secretory changes. The data obtained allow us to state the dysbiotic type of microbiota appears to be a marker of violation of the morphological characteristics of the endometrium during the "implantation window" phase, mainly against the background of a chronic inflammatory process. The dysbiotic profile of the endometrium in infertile women is the cause of a violation of molecular mechanisms necessary for adequate blastocyst implantation. The studying endometrial microbiota increases the likelihood of predicting reproductive outcomes before embryo transfer and choosing an effective treatment strategy when changing quantitative and qualitative species characteristics

 Materials and methods of research. 66 patients with a diagnosis of CPL COPR and 33 practically healthy individuals were examined. To characterize the intensity of SRO in the main and control groups, oral fluid was taken into test tubes after preliminary rinsing of the oral cavity with 10 ml of 0.9% sodium chloride solution. The intensity of free radical oxidation processes in the oral fluid was characterized by chemiluminescence (CML) on the LS 50B "PERKIN ELMER" spectrometer. Statistical processing of the results was carried out using methods of variational statistics.

 Results and discussion. Studies of chemiluminescence of mixed saliva in patients with CPL SOPR showed an increase in the generation of oxygen radicals and lipid peroxides: the Ssp value, confirming the intensity of production of toxic radicals, exceeded the identical indicator of the control group by 1.4 times (p< 0.05). Against the background of intensive generation of radical products (H) of mixed saliva in the main group, the indicator is 2.42 times (p<0.05) higher compared to the same indicator in practically healthy individuals, there was a decrease in the level of antioxidant antiradical protection (Sind-2) by 1.66 times (p<0.05), which indicates insufficient activity of the antioxidant defense system (AOS) of a patient with CPL SOPR. Chemiluminescence studies have shown that patients with CPL COPD revealed an imbalance between the processes of SRO and antioxidant protection, this is due to an increase in oxidant load and a decrease in antioxidant resources in mixed saliva in the main group compared with identical data in practically healthy individuals. The results obtained indicate the generation of free radical reactions in the group with CPL of the COPR.

Conclusion. An imbalance in the ratio of the processes of "formation of active metabolites – destruction of active metabolites" indicates hyperproduction of toxic SRO products in mixed saliva in patients with CPL COPR and disruption of work in the AOS system. The study of the activity of the SRO processes and the AOS system can be a condition for increasing the effectiveness of the therapy, by making adjustments to the standard treatment regimens of this category of patients, taking into account the functional state of the body's antioxidant barrier

The term "phacosurgery" combines various surgical technologies for the complete or partial removal of the lens. The last decades are characterized by an almost complete transition from extracapsular cataract extraction to the so-called. microinvasive phacosurgery, in particular, standard ultrasound and hybrid (femtolaser) phacoemulsification. Nevertheless, in a number of cases (for example, when the so-called brown cataract is combined with severe dystrophic changes in the cornea), extracapsular extraction, which involves the removal of the “whole” nucleus through a wide surgical incision in the limbal zone of the cornea, is still the method of choice for phacosurgery. The condition of the cornea after phacosurgery remains one of the criteria for the success of the intervention. In this case, as a rule, attention is focused on the "loss" of cells of the posterior epithelium and violations of the optical regularity of the cornea. Changes in corneal nerve fibers (CNF) have been studied to a lesser extent.

The aim of the study was to study the structural changes in CNF after extracapsular cataract extraction based on laser confocal microscopy.

The studies were conducted on the clinical material of 20 operations of extracapsular cataract extraction, which were performed on 20 patients aged 52 to 74 years. The condition of CNF was assessed before and after 7-10 days, 2-2.5 and 6 months after surgery, using the length and density of the main branches of CNF (in mm/mm2 and units/mm2, respectively) in the central zone of the cornea.

Regardless of the timing of follow-up, a decrease in the length and density of CNF was revealed with a moderate tendency to recovery by the 6th month after the intervention. Despite this, a statistically significant decrease in the average length of the main CNFs persisted during all periods of observation, and in density - for 2-2.5 months.

Factors that induce changes in CNF after various phacosurgery techniques include their intersection during the surgical incision and the energy impact on the cornea. When using microinvasive techniques, taking into account the minimization of the length of the incision, ultrasound and/ or laser radiation may be the dominant factor, and when using the extracapsular technique, the directly extended corneal incision, accompanied by the intersection of the CNF. In clinical practice, potential disturbances in the CNF structure after phacosurgery should be taken into account in situations accompanied by pronounced initial changes in CNF (condition after keratoplasty and excimer laser keratorefractive surgery, various types of systemic polyneuropathy)

The article presents first clinical cases with results of the molecular genetic confirmation of low-density lipoprotein receptor gene mutation in patients of the Lipid Cabinet of  SAI  RS(Ya) "Republican Clinical Hospital No.3" with the diagnosis of "probable" familial hypercholesterolemia.

In this work, the hearing analysis of 26 patients with hearing impairment, who had biallelic mutations of the GJB2 gene (Sh26) was carried out in the Republic of Buryatia. Genotype-phenotypic comparisons showed that for all 7 GJB2 genotypes: c.[35delG];[35delG]; c.[-23+1G>A];[35delG]; c.[-23+1G>A];[-23+1G>A]; c.[-23+1G>A];[516G>C]; c.[-23+1G>A];[327_328delGGinsA]; c.[35delC];[299_300delAT]; c.[235delC];[235delC] congenital (detected before one year – 76.0%), symmetrical (84.6%), sensorineural (100.0%) form of hearing loss are detected, variable in severity both between different GJB2 genotypes and within the same GJB2 genotype (grade III in 9.6%, grade IV in 17.3%, deafness in 73.1%). Based on the median hearing thresholds PTA_{0.5,1.0,2.0,4.0 kHz,} three phenotypes were identified - "mild phenotype", "medium phenotype" and "severe phenotype". We conducted a genotype-phenotypic comparison, as a result of which GJB2-genotypes c.[-23+1G>A];[-23+1G>A] and c.[-23+1G>A];[516G>C] were assigned to genotypes with “average” (median 66.875 dB and 64.375 dB, respectively), and the remaining GJB2-genotypes: c.[35delG];[35delG]; c.[-23+1G>A];[35delG]; c.[-23+1G>A];[327_328delGGinsA]; c.[35delC];[299_300delAT]; c.[235delC];[235delC] - to genotypes with a "severe" form of the phenotypic effect. No genotypes with a "mild" phenotypic effect have been identified. At the same time, the hearing thresholds for GJB2 genotypes with the "average" form of the phenotypic effect (c.[-23+1G>A(;)-23+1G>A] and c.[-23+1G>A(;)516G>C]) were significantly better (p=0.02268) than in the reference group with GJB2 genotype с.[35delG];[35delG].

Tobacco smoking is the most common form of addiction worldwide. The aim of our study was to determine whether the rs6311 polymorphisms of the HTR2A gene and the 5HTTLPR and rs25531 polymorphisms of the 5-HTT gene are associated with smoking in the Yakut population. The study involved 223 people, including 115 smokers and 108 non-smokers. The results of the analysis of the relationship between the rs6311 polymorphism of the HTR2A gene and smoking showed that in the group of smokers, allele A was somewhat more common than in the group of non-smokers (OR - 1.138, 95% CI = [0.742-1.138]). Analysis of the distribution of alleles and genotypes of the 5-HTTLPR polymorphism of the 5-HTT gene showed the predominance of the short S allele (74.8–89.4%) and the SS genotype (61.7–81.5%) in both samples. Smokers had a significantly (p<0.05) higher frequency of the risk allele L (OR -2.830, 95% CI= [1.674 -4.783]) compared to non-smokers. When analyzing the 5-HTTLPR and rs25531 polymorphisms grouped into groups, it was found that the frequency of the L' allele was four times higher in the sample of smokers (p<0.001) than in the sample of non-smokers (OR -4.844, 95% CI = [2.503-9.372]). An analysis of the distribution of combinations of genotypes of both studied genes showed the predominance of people with a combination of GG genotypes of the HTR2A gene and S'S' of the 5-HTT gene, which showed a protective effect on smoking (OR -0.550, 95% CI = [0.319-0.948]). A significant association with smoking was shown by a combination of heterozygous genotypes AG of the HTR2A gene and L'S' of the 5-HTT gene (OR -13.637, 95% CI= [1.752-106.144]). This study established a significant association of 5-HTT gene polymorphisms with smoking in the Yakut population. In connection with the equivalent serotonin expression of the S and LG alleles, 5HTTLPR and rs25531 polymorphisms, it is more informative to carry out their generalized analysis.

Amyotrophic lateral sclerosis (ALS) is a severe neurodegenerative disease in which the death of central and peripheral motor neurons occurs, leading to an inevitable fatal outcome. Bioethical problems arise at any stage of the disease when a patient with ALS goes to a doctor. The help of psychologists, the activities of bioethical committees in medical organizations in informing patients and their relatives about the disease, the awareness of neurologists about social support measures from the state can help in organizing medical and social assistance measures to improve the quality of life Aim: to solve the bioethical problems of patients with ALS to improve the organization of specialized medical care of patients with ALS.

This article describes the incidence of malignant neoplasms in the Sakha Republic’s population selected for screening studies and presents an assessment of the results of the Onkopoisk. Sakha (mass screening tests) pilot project. Screening is carried out for six types of malignant neoplasms that are an important problem for regional healthcare. In the course of screening, we carried out 12,826 tests and identified 21 cases of malignant neoplasms and 51 cases of precancerous conditions. The proportion of patients with stage 0-2 malignant processes was 62%.

Preliminary results of Onkopoisk.Sakha demonstrated how it can be useful in screening and early diagnosis of cancer in the Sakha Republic. This screening program using online platforms complements other activities of medical examinations and preventive examinations and is in demand because it meets the requirements of sanitary and epidemiological safety and saves resources.

A comprehensive survey of the working population of the Aldan district of the Republic of Sakha (Yakutia) was conducted. A total of 175 people of working age of non-indigenous nationality were examined. A high frequency of pathology on the part of the digestive, cardiovascular and endocrine systems, including the first identified, was revealed. Overweight and obesity had a high incidence, being a risk factor for the development of cardiovascular diseases. Every 10 respondents have registered oncopathology, 3 participants of the study were sent for further examination with suspicion of malignant neoplasms. The role of primary health care, including shop doctors, is of great importance in the early detection and prevention of risk factors for the most common chronic non-communicable diseases and timely effective medical care, as well as health schools for patients with hypertension, coronary heart disease, diabetes mellitus, gastritis, cancer, etc

In the Republic of Sakha (Yakutia), the incidence of malignant neoplasms of the urinary system from 2001 to 2015 increased by 1.9 times. The quality of the surface waters of the Lena River and its basin is affected by the economic activities of mining, energy, utilities, water transport, oil depots, agriculture with direct discharge of wastewater into them, as well as due to the ingress of pollutants into the adjacent settlements. territories. The purpose of the study is to assess the relationship between the incidence of malignant neoplasms of the urinary system organs and hydrochemical factors polluting the aquatic environment in the Prilensky zone of Yakutia. Correlation analysis was performed on the data on the incidence of MNs in the organs of the urinary system of the population (2001-2015) and the data on the chemical composition of water in the Prilensky zone of Yakutia (1979-1985). The results of the analysis indicate that Yakutia belongs to the territories with a rather pronounced contrast in terms of the incidence of cancer of the urinary system. It can be assumed that the territorial variability in the number of people with cancer of the urinary system organs may well be a reflection of the correlation of the incidence rate, both exogenous and endogenous "risk factors". During the analyzed period, strong direct correlations were established between the parameters of the urinary tract organs with the level of chlorides and synthetic surfactants (surfactants). Correlations of average strength with the level of nitrites, magnesium, transparency, color and mineralization of water in the territories of the Lena zone for 1979-1985 were also revealed.

An analysis of the main biochemical parameters of the population living in the territory with unfavorable natural radioactivity of 222Rn revealed changes in the biochemical spectrum of blood serum in the population of the Aldan region, indicating the presence of signs of disadaptation. Lipid profile changes are associated with gender and smoking. The shift of lipid metabolism towards atherogenicity is more pronounced in men due to an increase in the atherogenic fractions of lipids in the blood that are susceptible to peroxidation and a decrease in the level of the antiatherogenic fraction of lipids. The shift of metabolic flows towards catabolism, activation of glycolysis, dyslipidemia indicate the tension of carbohydrate and lipid metabolism, which is a sign of disadaptation of the body and the risk of developing environmentally conditioned diseases, including neoplasms.

The article presents an analysis of the state statistical reporting data on the disability of the population of the Irkutsk region due to HIV infection, dispensary observation of patients with HIV infection. The long-term dynamics of changes in the 4th stage of HIV infection depending on secondary manifestations is shown. The median of the average age of patients by disability groups among men and women was calculated, the structure of the causes of disability was presented. A forecast is given regarding the change in disability groups for 2022. Measures to increase the adherence of citizens with HIV infection to antiretroviral therapy, the prevention of secondary and opportunistic diseases will prevent early disability of the population.

This article carried material about the results of the investigation of peripheral blood cellular immunity parameters in the COVID-19 patients with ≤30% lung damage hospitalizated in 2020 year. When infected with SARS-CoV-2 on the background of severe lymphopenia and neutrophilia were revealed the multidirectional changing in a cellular immunity parameters, the severity and dynamics of which can be determined by the initial type of immune system response

Excess mortality is defined as an increase in all-cause mortality over expected mortality (historical baseline for previous years). In the context of COVID-19, excess mortality may reflect the overall impact of the pandemic on mortality, including not only the number of confirmed deaths from COVID-19, but also deaths from COVID-19 when they were not correctly diagnosed and reported, and deaths from other diseases due to pandemic-related causes.

The purpose of the study: to assess the indicators of excess mortality during the COVID-19 pandemic (2020-2021) in the Republic of Sakha (Yakutia). For the analysis, data from the Federal State Statistics Service for 2015-2022 were used. For 2 years of the spread of a new coronavirus infection in the Republic of Sakha (Yakutia), 19556 people died. 7.8% of deaths in 2020 and 21.5% in 2021 were related to COVID-19. The number of all deaths was 22% and 44% respectively higher than the expected number of deaths. The proportion of excess deaths in 2020 was 19% of all deaths, in 2021 - 31%. Of the excess deaths, 42% and 69%, respectively, were related to COVID-19. The excess mortality rate reached 333 per 100,000 population in 2021. The high correlation coefficients (0.94-0.95) between COVID-19-related deaths and additional deaths suggest that excess deaths during the period 2020-2021 will largely be due to the spread of COVID-19.

The decline in mortality underreporting in 2021 against the background of an increase in excess mortality reflects improved diagnosis and correct identification of the causes of death. Research into the causes of excess mortality is needed to assess the impact of the pandemic and other factors on various aspects of mortality in the population

We have analyzed the impact of herpes virus infection on the course of a new coronavirus infection (NCVI). Infection of the examined contingent with herpes family viruses reached 95.3-100%. An association of NCVI with herpes simplex viruses 1, 2 types (HSV 1, 2 types) was found, but no correlation was found between the positivity coefficient (CP) of HSV 1, type 2 and the severity of NCVI. This can be explained by the fact that the sampling was carried out in the remote period after the transferred NKVI. Considering that both herpes viruses and the SARS-CoV-2 virus cause multiple organ damage and can aggravate each other, the study of co-infection seems to be very relevant.

According to the results of the study, when infected with the SARS-CoV-2 virus, lipid metabolism is disturbed: in the acute period of infection, the level of total cholesterol decreases, in the post-COVID period, its level significantly increases. The most pronounced shift in the lipid profile towards atherogenicity occurs in patients who recovered from COVID-19 three months ago due to a decrease in the antiatherogenic fraction of lipids. Dyslipidemia is most pronounced in patients who have had an infection with severe lung damage (50-75%) due to an increase in atherogenic lipid fractions that create a risk of atherosclerosis.

A survey of 56 practically healthy men from among the indigenous inhabitants of Yakutia (yakuts-34, evenks-22) was carried out. The average age of men was 40.1±1.58 years. The purpose of this study was to assess the psycho-emotional state and the level of neurosteroid hormones in men of the indigenous population of the Republic of Sakha (Yakutia). The results of a psycho-emotional study of men showed that good psychological adaptation was noted in 64.3% (37), of which the «health» level was 28.6% (16) and optimal adaptation was 35.7% (20). Non-pathological maladaptation was detected in 16.1% (9), and severe pathological maladaptation - in 19.6% (11) (pathological mental maladjustment - 8.9% (5) and probably a disease state - 10.7% (6)). Depression (D) was absent in 35.7% (20), mild depression was noted in 17.8% (10), moderate in 28.6% (16) and severe in 17.8% (10), severe depression not identified. An analysis of the degree of aggression showed that in 42.9% (24) of the surveyed, the aggression index (IA) was normal, in 53.6% (30) it was low and in 3.6% (2) it was high. An increase in the level of neurosteroid hormones in indigenous men is a protective reaction of the body in ensuring homeostasis and adaptation to the conditions of the North. The concentration of steroid hormones in men decreases with the deterioration of the psycho-emotional state.

The features of cellular and humoral immune responses in the inhabitants of the European North and the Arctic have been studied. It has been established that a parallel increase in the frequency of registration of erythrocytosis, thrombocytosis, elevated hemoglobin, hematocrit and thrombocrit in residents of the Murmansk region is a mechanism for adaptation to an increased need for O₂ in the Arctic. The examined individuals showed a high frequency of registration of leukocytosis, lymphocytosis, neutrophilia, monocytosis, eosinophilia and basophilia against the background of a significant level of deficiency of active phagocytes. A feature of the immunological reactivity of the inhabitants of the polar village is the predominance of reactions of cell-mediated and antibody-dependent cytotoxicity against the background of an increase in pro-inflammatory cytokines IL-6, IFN-γ, reagins, intercellular adhesion molecules sCD54 and sCD62L.

Previously, the m.1555A>G mutation in the MT-RNR1 gene associated with the mitochondrial form of hearing loss was detected in one patient from Eveno-Bytantaisky district of Yakutia. The aim of this work is to study the mitochondrial form of hearing loss in this region of Yakutia, which probably has a local focus of accumulation of the m.1555A>G mutation in the MT-RNR1 gene. In the work, a clinical-genealogical, clinical-audiological and molecular-genetic examination of 72 residents of Eveno-Bytantaisky district was carried out for the presence of the m.1555A>G mutation in the MT-RNR1 gene of mitochondrial DNA. As a result of molecular genetic analysis, among the examined individuals, the m.1555A>G mutation was found in 6 people. Clinical and genealogical analysis, carried out up to the fifth generation, revealed that these six individuals belong to three families (including 25 deaf people). In the examined individuals with the m.1555A>G mutation of the MT-RNR1 gene, clinical phenotype variability was revealed - from normal hearing to bilateral hearing loss of III degree, with a late debut (onset from 30 to 60 years). The revealed variability is probably due to incomplete penetrance and requires further extensive research aimed at searching for genes that modulate nuclear or mitochondrial genomes.

The article presents an overview of the role of assorted deafness marriages in the spread of hereditary hearing loss. In 1883, Alexander Graham Bell, the famous inventor of the telephone, first suggested that frequent marriages between deaf people could lead to an increase in the incidence of deafness, but this hypothesis was not recognized by his contemporaries. In the 2000s, with the development of molecular genetic studies, which made it possible to identify one of the most common forms of hearing loss due to gene mutations GJB2, connexin 26, which encodes the interstitial contact protein, has been reinterpreted by Walter Nance. In the series of studies, he and his coauthors were able to show that the reproductive capabilities of the deaf have increased, and marriages between the deaf occur not by chance, but by the principle of assortativity, which in total could lead to an increase in the prevalence of one of the most frequent "connexin" forms of hearing loss.

A review of the literature on the role of neuropilin-1 in the development of SARS-CoV-2 infection and a search for probable links between polymorphic variants of the NRP1 gene and SARS-CoV-2 are presented. This review presents the characteristics of polymorphic variants of the NRP1 gene, which demonstrate the possibility of their association with the course of SARS-CoV-2 infection.

The results of detection of DNA fragments encoding human beta-globin and human papillomavirus L1 protein in plasma and erythrocyte samples from a cervical cancer patient using real-time polymerase chain reaction (qPCR) are presented. Amplification of a DNA fragment encoding human beta-globin was found only in a sample of erythrocytes, which may indirectly indicate the presence of extracellular DNA. The results of qPCR for the presence of a DNA fragment encoding HPV L1 were negative, which did not allow us to confirm that the isolated DNA belonged to the tumor DNA. The origin of the identified in the erythrocyte fraction DNA fragment encoding human beta-globin requires further research.

The issues of translational medicine in the field of implementation of the results of molecular genetic studies in the practical medicine of Yakutia are discussed. The process of phased introduction of its main directions is noted: "Discovery", "Population research", "DNA diagnostics", "Bioethical research", "State programs for the prevention of hereditary diseases". The use of new technologies has raised the health care of the Republic of Sakha (Yakutia) to a qualitatively new level, but at the same time brought a lot of intractable ethical, legal and informational problems. It is necessary to raise the issue of the importance of adopting state programs for the prevention and treatment of hereditary diseases in the Republic of Sakha (Yakutia).

The aim of this study is to test the hypothesis that personality traits (neuroticism, extraversion/ introversion) and stressful life events in childhood could be related to HPA axis reactivity. We studied 121 healthy adult men of Yakut ethnicity aged 18–25 years. High neuroticism and introversion have been found to be associated with lower blood cortisol. Stressful life events have been positively associated with neuroticism, but we failed to detect a significant correlation with ACTH and serum cortisol levels in young people.

Тhe article describes a case of ultrasound diagnostics of non-compact left ventricular myocardium. Echocardiography allowed establishing a rare congenital pathology of the left ventricular myocardium.

A clinical case of a fatal thrombotic complication in a patient with a new coronavirus infection (NCVI) COVID-19 in the convalescent period is presented. A retrospective analysis of the patient's medical record with the chronology of laboratory and instrumental studies, the clinical course and the applied methods of intensive care was carried out. The algorithm of pulmonary embolism (PE) diagnosis, validity and decision-making concerning thrombolytic therapy and extracorporeal membrane oxygenation are shown. The results of autopsy are  presented as well , confirming the diagnosis of PE and the appropriateness of medical interventions

We describe a case of early ultrasound prenatal diagnosis of a rare disabling malformation of the fetal central nervous system, lower occipital encephalocele, at 13/3 weeks of pregnancy. The article describes the characteristic ultrasound markers, stages of prenatal ultrasound diagnostics. The prenatal diagnosis was established on the basis of the signs characteristic of this pathology of the central nervous system. The pregnancy was terminated at 17 weeks by the decision of the family. Pathomorphological examination of abortus confirmed the echographic changes detected in the prenatal periodю

Currently no more than 300 patients with partial red cell aplasia have been described. The article presents a rare case of partial red cell aplasia in a Sakha child

Dementia is a chronic cognitive decline affecting all domains of cognition with an unfavorable outcome, observed in both dementia with Lewy bodies (DLB) and Parkinson's disease (PD). These two conditions belong to the group of alpha-synucleinopathies. In DLB and PD, attention, goal-directed activity, visual-spatial orientation, visual-constructive ability, and memory are affected. The similarity of the profile of cognitive impairment in PD with dementia and DTL leads to some difficulties in the diagnosing of these two diseases. Using their own observations, the authors have demonstrated that an important aspect in making the correct diagnosis is objective information from relatives and analysis of the available medical records.