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The article examines the socio-demographic aspects of managing the quality of life of the population in modern conditions. The standard of living of the population is a complex socio-economic parameter that reflects the combined impact of various factors on the nature of the consumer ability of citizens and the ability to maintain a certain lifestyle. Globalization processes in the global economy increase interest in the problem of effective management of the standard of living of the population, since the indicators used to assess the quality of life of the population characterize the development of socio-economic relations in the state. In conclusion, it is concluded that the category «quality of life of the population¼ is an important indicator of the effectiveness of public management of socio-demographic processes, and demographic processes are one of the key factors in the indicator of the quality of life of the population.

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The health of the population is the highest value, therefore, an effectively functioning system of protecting the health of citizens is the most important priority of regional socio-demographic policy and national security. The purpose of the study is to consider the most important priority of socio-demographic policy - capital management of public health in the regions of the Russian Federation. The relevance of the research topic is due to the fact that currently the conditions of the domestic health care system are extremely complex. Health capital management is a key socio-demographic task on a global scale, which ensures well-being both from the perspective of current socio-economic development, which is measured by the efficiency of the use of human capital, and from the point of view of the long-term effect of improving people's lives.

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Last data demonstrated that exonic variants of LRRK2 (p.G2019S, p.M1646T) may affect the catalytic activity of lysosomal enzyme glucocerebrosidase (GCase) probably through the phosphorylation of Rab10 protein. We aimed to evaluate an association of LRRK2 exonic variants previously associated with alteration of phosphorylation levels for Rab10Thr73 with PD risk in Russian population and analyze an impact of p.G2019S mutation and selected LRRK2 variants on lysosomal hydrolase activities. LRRK2 variants were determined by full sequencing of LRRK2 in 508 PD patients and 470 controls from Russian population. Activity of lysosomal enzymes (glucocerebrosidase (GCase), alpha-galactosidase A (GLA), acid sphingomyelinase (ASMase) and concentrations of their corresponded substrates (hexosylsphingosine (HexSph), globotriaosylsphingosine (LysoGb3), lysosphingomyelin (LysoSM), respectively) were estimated in 211 PD patients and 179 controls by liquid chromatography with tandem mass spectrometry (LC-MS-MS) in dry blood spots. p.M1646T and p.N2081D were associated with PD (OR = 2.33, CI 95%: 1.1215 to 4.8253, p = 0.023; OR = 1.89, 95%CI: 1.0727 to 3.3313, p = 0.028, respectively) in Russian population. An increased LysoGb3 concentration was found in p.G2019S and p.N2081D LRRK2 carriers among PD patients compared to both PD patients and controls (p.G2019S: p = 0.00086, p = 0.0004, respectively; p.N2081D: p = 0.012, p = 0.0076, respectively). A decreased ASMase activity in p.G2019S LRRK2 carriers among PD patients (p = 0.014) was demonstrated as well. Our study supported possible involvement of LRRK2 dysfunction in an alteration of sphingolipid metabolism in PD.

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This article focuses on modeling 90Sr migration in strong nitrate solutions in aquifers used for radioactive waste disposal. This type of radioactive waste disposal is typical only for the Russian Federation and is a unique object of study. The calculations are based on the laboratory study of strontium sorption in nitrate solutions on sandy, loamy and clayey rocks under biotic (with natural microbial communities obtained from Seversky repository) and abiotic conditions. To obtain a strontium sorption model, first, an ion exchange model in PHREEQC software is fitted to the experimental data both manually and automatically (using MOUSE software). Since real nitrate-ion concentrations at radioactive waste injection sites can reach values of hundreds of grams per liter, strontium Kd values are predicted for high ionic strength (for which no experimental study of strontium sorption efficiency has been carried out) with PHREEQC-model. The strontium transport models accounting for sorption and the nitrate reduction processes have been developed using two numerical software packages: the GeRa 3D hydrogeological simulation code and the PHREEQC reactive transport code. Reactive transport modeling under different conditions shows a high sensitivity to dispersion. A significant effect of sorption of nitrate ion on Sr sorption is shown and a relatively small contribution of microbial processes to strontium transport is noted for liquid radioactive waste injection sites.

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BACKGROUND:  X-linked adrenoleukodystrophy (X-ALD) is a severe neurodegenerative metabolic disease with a frequency 1:17,000 in newborn boys. Being a major part of X-ALD with an incidence of 70-80% of patients, adrenal insufficiency (AI) is a life-threatening condition without timely treatment. The possibility of developing AI during the whole disease duration and the absence of any predictive factor for AI joining shows the necessity of studying AI in X-ALD patients to optimize current diagnostic and treatment algorithms. AIM:  To study diagnostic and therapeutic features of primary adrenal insufficiency due to X-ALD. MATERIALS AND METHODS:  A retrospective observational comparative study was conducted in 66 male patients, examined and treated in the Pediatric endocrinology department of Endocrinology Research Centre, Research Centre for Medical Genetics, Research and Clinical Institute for Pediatrics of the Pirogov Russian National Research Medical University Detached Structural Unit Russian Children's Clinical Hospital (Moscow, Russia) for 2014-2022. All of patients were diagnosed with primary AI and a genetically confirmed X-ALD. RESULTS:  The median age of X-ALD manifestation was 6.6 years [4.7; 11.1]. The earliest age of AI diagnosis was 1.5 years at the preclinical stage and 1 year 8 months with clinical symptoms. The renin level was studied in 22.7% at the manifestation of AI (15/66 patients), mineralocorticoid deficiency was found in 7 patients. Family history was positive in 39.4% of patients (n=66), only in 15.1% (10/66 patients) of patients the disease was established at the preclinical stage. In 59.1% (n=66) the cerebral form of the disease (cALD) was established, in 16.6% - adrenomyeloneuropathy (AMN), and in 24.2% - isolated adrenal insufficiency (PAI). Age of AI establishment in the group of patients with AMN (15.6 years) significantly differs from the establishment of AI in patients with cALD (7.4 years, p=0.001) and PAI (5.6 years, p = 0.000). Mineralocorticoid therapy was prescribed simultaneously with glucocorticoid therapy in patients with cALD, in AMN and PAI patients it was added after 11 and 7 months, respectively (the differences between AMN and PAI groups were insignificant). Combined hormonal therapy receive 41% of patients with cALD, 54.5% of patients with AMN and 60% of patients with PAI. CONCLUSION:  It is necessary to examine all male patients with AI regardless of the manifestation age to exclude adrenoleukodystrophy, and it is also important to examine patients for the presence of AI regardless of X-ALD manifestation age. The assessment of renin level in the manifestation of AI is also needed to prescribe mineralcorticoid therapy timely. Studying family history is the main method to detect X-ALD at the preclinical stage.

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The synucleinopathies are a group of neurodegenerative diseases characterized by the oligomerization of alpha-synuclein protein in neurons or glial cells. Recent studies provide data that ceramide metabolism impairment may play a role in the pathogenesis of synucleinopathies due to its influence on alpha-synuclein accumulation. The aim of the current study was to assess changes in activities of enzymes involved in ceramide metabolism in patients with different synucleinopathies (Parkinson's disease (PD), dementia with Lewy bodies (DLB), and multiple system atrophy (MSA)). The study enrolled 163 PD, 44 DLB, and 30 MSA patients as well as 159 controls. Glucocerebrosidase, alpha-galactosidase, acid sphingomyelinase enzyme activities, and concentrations of the corresponding substrates (hexosylsphingosine, globotriaosylsphingosine, lysosphingomyelin) were measured by liquid chromatography tandem-mass spectrometry in blood. Expression levels of GBA, GLA, and SMPD1 genes encoding glucoceresobridase, alpha-galactosidase, and acid sphingomyelinase enzymes, correspondently, were analyzed by real-time PCR with TaqMan assay in CD45 + blood cells. Increased hexosylsphingosine concentration was observed in DLB and MSA patients in comparison to PD and controls (p < 0.001) and it was associated with earlier age at onset (AAO) of DLB (p = 0.0008). SMPD1 expression was decreased in MSA compared to controls (p = 0.015). Acid sphingomyelinase activity was decreased in DLB, MSA patients compared to PD patients (p < 0.0001, p < 0.0001, respectively), and in MSA compared to controls (p < 0.0001). Lower acid sphingomyelinase activity was associated with earlier AAO of PD (p = 0.012). Our data support the role of lysosomal dysfunction in the pathogenesis of synucleinopathies, namely, the pronounced alterations of lysosomal activities involved in ceramide metabolism in patients with MSA and DLB.

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Activity of extracellular enzymes was assessed in 20 strains of microscopic fungi involved in biodegradation of technical objects exploited under tropical climate conditions (Vietnam). It was found that 19 strains possessed catalase activity, 18 strains had phenol oxidase activity, and eight strains had protease activity. The effect of industrial biocides on the activity of these enzymes was also assessed. The biocides Bior-1, Bioneutral A 10, and Bioneutral A 101 were shown to inhibit the enzymatic activity to various extent. All biocides inhibited extracellular catalase activity in most fungal strains studied. The inhibition of protease and phenol oxidase activity of same test strains was less pronounced. The response to biocides varied at the strain level; its characteristics could differ significantly even between strains of the same species. In several cases, it was observed that exposure to biocides resulted in an increase in enzyme activity.

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The paper describes a case of a perinatal lethal Gaucher disease in a 29-week-old fetus with non-immune hydrops, facial dysmorphia, hepatosplenomegaly, and hypoplasia of cerebellum and pons. Gaucher cells were found in the lymph nodes, spleen, lungs, thymus, cerebellum, and bone marrow. No storage cells have been detected in the placenta. There was a significant placental weight increase due to swelling. The diagnosis of Gaucher disease was confirmed by biochemical analysis (deficiency of glucocerebrosidase activity and sharply increased hexanoylsphingosine concentration) and molecular genetic techniques (the presence of two mutations of the GBA gene). Our observation shows that characteristic histologic signs of disease can be detected at early stages of development.

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The article demonstrates that over the past few years medical tourism market goes through significant changes . This especially relates to regional economy and its aspects in the field of tourism. The article presents an important conclusion that nowadays the top-priority factor in the development of medical tourism is a number of crisis points in provision of health tourism services both in the regions of Russia and in the capital region that are related to pandemic and its consequences. The article considers complex of factors related just to epidemiological crisis and its consequences? including economic and social factors related to health-preserving technologies of medical tourism industry. The actual condition of tourism industry, as a branch of the Russian economy,demonstrates that it was among the first ones hit by the pandemic. The article emphasizes that due to emerging problematic trends during epidemics and their aftermaths the possibilities of providing medical tourism services and their concentration in the country, costs and conditions are changing that undoubtedly impact the economic component and health ecology aspects. The conclusion is made that among main conditions of adjustment of medical tourism industry to the new economic conditions are to be truly multidimensional and structured directions and tools that can be applied to look for way out of difficult situations when sales of medical services have fallen to zero, and companies are forced to work out on solutions emerging problems and to make plans of operational way out of existing crisis.

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Mutations in the glucocerebrosidase gene (GBA) encoding the lysosomal enzyme glucocerebrosidase (GCase) cause Gaucher disease (GD) and are the most commonly known genetic risk factor for Parkinson disease (PD). Ambroxol is one of the most effective pharmacological chaperones of GCase. Fourteen GD patients, six PD patients with mutations in the GBA gene (GBA-PD), and thirty controls were enrolled. GCase activity and hexosylsphingosine (HexSph) concentration were measured in dried blood and macrophage spots using liquid chromatography coupled with tandem mass spectrometry. The effect of ambroxol on GCase translocation to lysosomes was assessed using confocal microscopy. The results showed that ambroxol treatment significantly increased GCase activity in cultured macrophages derived from patient blood monocytic cell (PBMC) of GD (by 3.3-fold) and GBA-PD patients (by 3.5-fold) compared to untreated cells (p < 0.0001 and p < 0.0001, respectively) four days after cultivation. Ambroxol treatment significantly reduced HexSph concentration in GD (by 2.1-fold) and GBA-PD patients (by 1.6-fold) (p < 0.0001 and p < 0.0001, respectively). GD macrophage treatment resulted in increased GCase level and increased enzyme colocalization with the lysosomal marker LAMP2. The possible binding modes of ambroxol to mutant GCase carrying N370S amino acid substitution at pH 4.7 were examined using molecular docking and molecular dynamics simulations. The ambroxol position characterized by minimal binding free energy was observed in close vicinity to the residue, at position 370. Taken together, these data showed that PBMC-derived macrophages could be used for assessing ambroxol therapy response for GD patients and also for GBA-PD patients.

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Currently, pathogenic variants in more than 25 nuclear genes, involved in mtDNA maintenance, are associated with human disorders. mtDNA maintenance disorders manifest with a wide range of phenotypes, from severe infantile-onset forms of myocerebrohepatopathy to late-onset forms of myopathies, chronic progressive external ophthalmoplegia, and parkinsonism. This study represents the results of molecular genetic analysis and phenotypes of 102 probands with mtDNA maintenance disorders. So far, this is the largest Russian cohort for this group of diseases. Mutations were identified in 10 mtDNA maintenance genes: POLG (n = 59), DGUOK (n = 14), TWNK (n = 14), TK2 (n = 8), MPV17 (n = 2), OPA3 (n = 1), FBXL4 (n = 1), RRM2B (n = 1), SUCLG1 (n = 1) and TYMP (n = 1). We review a mutation spectrum for the DGUOK and TWNK genes, that can be specific for the Russian population. In 34 patients we measured the blood mtDNA copy number and showed its significant reduction. Novel variants were found in 41 cases, which significantly expands the mutational landscape of mtDNA maintenance disorders.

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Mutations in the IDUA gene cause deficiency of the lysosomal enzyme alpha-l-iduronidase (IDUA), which leads to a rare disease known as mucopolysaccharidosis type I. More than 300 pathogenic variants of the IDUA gene have been reported to date, but not much is known about the distribution of mutations in different populations and ethnic groups due to the low prevalence of the disease. This article presents the results of a molecular genetic study of 206 patients with mucopolysaccharidosis type I (MPS I) from the Russian Federation (RF) and other republics of the former Soviet Union. Among them, there were 173 Russian (Slavic) patients, 9 Tatars, and 24 patients of different nationalities from other republics of the former Soviet Union. Seventy-three different pathogenic variants in the IDUA gene were identified. The common variant NM_000203.5:c.208C>T was the most prevalent mutant allele among Russian and Tatar patients. The common variant NM_000203.5:c.1205G>A accounted for only 5.8% mutant alleles in Russian patients. Both mutations were very rare or absent in patients from other populations. The pathogenic variant NM_000203.5:c.187C>T was the major allele in patients of Turkic origin (Altaian, Uzbeks, and Kyrgyz). Specific own pathogenic alleles in the IDUA gene were identified in each of these ethnic groups. The identified features are important for understanding the molecular origin of the disease, predicting the risk of its development and creating optimal diagnostic and treatment tools for specific regions and ethnic groups.

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Safe disposal of nuclear waste in a geologic repository will rely on natural geologic features and engineered barriers to greatly retard the movement of radionuclides from the repository. Clay minerals including bentonite are effective in retarding the migration of many radionuclides, but are ineffective for anionic radionuclides, of which pertechnetate is of particular concern owing to its relatively long half-life and the lack of natural isotopes that dilute it. Activated carbon is proposed as an additive material for reducing pertechnetate mobility in the nearfield. Activated carbon materials of different origins quantitatively sorb pertechnetate from aqueous solution under oxidizing conditions during the first day of contact, and sequential extraction showed that 73 % of this technetium is in the strongly bound fraction. X-ray photoelectron spectra (XPS) and extended X-ray absorption fine structure (EXAFS) spectra both demonstrated that no reduction of technetium occurred in the studied systems. The interaction of technetium with a composite material consisting of bentonite and activated carbon was studied at the first time. Effective technetium sorption was shown, with distribution coefficients (Kd) up to 740 cm3. g-1.

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Lysosomal integral membrane protein-2 (LIMP-2), encoded by the SCARB2 gene, is the specific lysosomal receptor for glucocerebrosidase enzyme. Association between rs6812193 and rs68250047 of SCARB2 with PD has been shown in genetic studies, including large genome-wide association studies. The aim of the current study was to determine whether rs6812193 and rs8475 are associated with PD in Russia. rs6812193 and rs8475 were genotyped in a total of 604 PD patients (65 PD patients with positive (fPD) and 539 PD patients with negative family history (sPD)) and 413 controls and also in 17 patients with PD associated with GBA mutations (PD-GBA) and 18 asymptomatic GBA mutation carriers (GBA-Carriers). SCARB2 expression was measured by real-time PCR in CD45+ blood cells in part of individuals in the studied groups. No linkage disequilibrium was shown between rs6812193 and rs8475 in Russian population. Increased PD risk for TT variant of rs8475 (OR = 2.02; p < 0.001) was found in sPD patients but not in fPD. rs6812193 and rs8475 were not associated with age at onset (AAO) of PD. SCARB2 expression level was decreased in GBA-PD patients and GBA-Carriers compared to PD patients (padjusted = 0.02, padjusted = 0.003, respectively) and GBA-Carriers compared to controls (padjusted = 0.013) with no significant difference in PD patients and controls. SCARB2 expression was not modified with rs6812193 and rs8475. In conclusion, rs8475 was associated with PD status. rs6812193 and rs8475 are not genetic modifier of AAO of PD and do not influence on SCARB2 mRNA level in CD45+ blood cells in studied groups. SCARB2 expression could be modified with GBA mutations and is independent of PD status.

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Monoclonal gammopathy of renal significance (MGRS) is a new nosology in modern nephrology and oncohematology. MGRS is defined as kidney injury due to nephrotoxic monoclonal immunoglobulin produced by the B-cell line clone which does not reach the hematological criteria for specific treatment initiation. Monoclonal proteins pathological effects on kidney parenchyma result in irreversible decline of kidney function till the end stage renal disease that in line with the position of International Consensus of hematologists and nephrologists determinates critical necessity for clone specific treatment in patients with MGRS despite the absence of hematological indications for treatment initiation. Main challenge of MGRS in Russian Federation is an inaccessibility of an in-time diagnostic and appropriate treatment for the great majority of patients due to the following reasons: 1) limited knowledge about the MGRS among hematologists and nephrologists; 2) lack of necessary diagnostic resources in most health-care facilities; 3) lack of approved clinical recommendations and medical economic standards for treatment of this pathological entity. Consensus document comprises the opinion of experts leading nephrologists and hematologists of Russian Federation on the problem of MGRS including the incoherence in nosology classification, diagnostics approach and rationale for clone specific treatment. Consensus document is based on conclusions and agreements reached during the conference of leading nephrologists and hematologists of Russia which was held in the framework of symposia Plasma cell dyscrasias and lymphoproliferative diseases: modern approaches to therapy, 1516 of March 2019, Pavlov First Saint Petersburg State Medical University. The present Consensus is intended to define the principal practical steps to resolve the problem of MGRS in Russian Federation that are summarized as final clauses.

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Fabry disease (FD [MIM:301500]) is an X-linked lysosomal storage disorder caused by mutations in the GLA gene. Deficient activity of its product, lysosomal enzyme α-galactosidase A (α-Gal A), leads to excessive accumulation of glycosphingolipids in cells of multiple organs. The establishing of the diagnosis is challenge in female patients because of milder clinical manifestation and normal α-Gal A activity. The globotriaosylsphingosine (lysoGb3) is described as a more sensitive diagnostic biomarker for females with pathogenic mutation in the GLA gene. Thus, the aim of this study is to improve the biochemical diagnostic efficiency for FD in females. Here we report the α-Gal A/lysoGb3 ratio as the novel biochemical criteria for diagnosis of female patients with FD, using dried blood spots (DBS) as test samples. It showed 100% sensitivity in distinguishing our group of 35 female patients from control (n = 140). Whereas measurement of α-Gal A and lysoGb3 alone showed 8.6% and 74.4% respectively. A new approach of using the ratio of α-Gal A activity to lysoGb3 concentration in DBS may provide a more accurate screening tool for identification of FD females.

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Self-incompatibility (SI) is genetically determined reproductive barrier preventing inbreeding and thereby providing the maintenance of plant species diversity. At present, active studies of molecular bases of SI mechanisms are underway. S-RNAse-based SI in Petunia hybrida L. is a self-/non-self recognition system that allows the pistil to reject self pollen and to accept non-self pollen for outcrossing. In the present work, using fluorescent methods including the TUNEL method allowed us to reveal the presence of markers of programmed cell death (PCD), such as DNA fragmentation, in growing in vivo petunia pollen tubes during the passage of the SI reaction. The results of statistical analysis reliably proved that PCD is the factor of S-RNAse-based SI. It was found that preliminary treatment before self-pollination of stigmas of petunia self-incompatible line with aminooxyacetic acid (AOA), inhibitor of ACC synthesis, led to stimulation of pollen tubes growth when the latter did not exhibit any hallmarks of PCD. These data argue in favor of assumption that ethylene controls the passage of PCD in incompatible pollen tubes in the course of S-RNAse-based SI functioning. The involvement of the hormonal regulation in SI mechanism in P. hybrida L. is the finding observed by us for the first time.

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Lysosomal acid lipase deficiency (LALD; MIM#278000) is a continuum of autosomal recessive diseases caused by defects in the gene LIPA and historically divided into two phenotypes: severe infantile-onset form called Wolman disease (WD) and childhood/adult-onset form known as cholesteryl ester storage disease (CESD). We report a novel synonymous homozygous variant c.600G > A in LIPA of a patient with LALD. Functional analysis of the patient cDNA and minigene assay revealed this variant as the cause of exonic cryptic splice site activation and 63 b.p. deletion in exon 6. To investigate the impact of this in-frame deletion on protein function, we performed 3D modeling of the human lysosomal acid lipase and showed the alteration of highly conservative region in close proximity to protein active site, which may completely eliminate the enzymatic activity. Using transcript specific real-time quantitative PCR method, we evaluated the relative ratio of the patient's wild type transcript isoform which is significantly reduced and correlates with severe childhood-onset variant of LALD.

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BACKGROUND: Hunter syndrome (mucopolysaccharidosis type II) is a recessive X-linked disorder due to mutations in the iduronate 2-sulfatase (IDS) gene. The IDS gene encodes a lysosomal enzyme, iduronate 2-sulfatase. The disease occurs almost exclusively in males. However, in the literature, 12 cases of the disease in females are known due to structural anomalies, a non-random chromosome X inactivation or chromosome X monosomy. The purpose of this article is to demonstrate a rare case of Hunter syndrome in a girl caused by a mutation in the IDS gene inherited from the mother and the presence of chromosome X of paternal origin, partially deleted in the long arm region - 46,X,del(X)(q22.1). CASE PRESENTATION: Girl M., 4 years old, entered the hospital with growth retardation, pain in the lower limbs, and joint stiffness, noted from the age of 18 months. After the karyotype analysis, which revealed a partial deletion of the long arm of chromosome X - 46, X, del (X) (q 22.1), Turner syndrome was diagnosed. However, due to the hurler-like facial phenotype, Hurler syndrome or type I mucopolysaccharidosis (MPS) was suspected. The study of lysosomal enzymes showed normal alpha-L-iduronidase activity and a sharp decrease in the activity of iduronate sulfatase in the blood: 0.001 µM/l/h, at a rate of 2.5-50 µM/l/h. Molecular genetic analysis revealed a hemizygous deletion in the IDS gene, which was not registered in the international Human Gene Mutation Database (HGMD) professional. This deletion was not detected in the girl's father, but was detected in her mother in the heterozygous state. CONCLUSIONS: Thus, the girl confirmed comorbidity - Turner syndrome with a partial deletion of the long arm of chromosome X of paternal origin, affecting the Xq28 region (localization of the IDS gene), and Hunter syndrome due to a deletion of the IDS gene inherited from the mother. The structural defect of chromosome X in the girl confirmed the hemizygous state due to the mutation in the IDS gene, which has led to the formation of the clinical phenotype of Hunter syndrome.

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BACKGROUND: Hereditary tyrosinemia (HT1) is an autosomal recessive disorder characterized by impaired tyrosine catabolism because of fumarylacetoacetate hydrolase deficiency. HT1 is caused by homozygous or compound heterozygous mutations in the FAH gene. The HT1 frequency worldwide is 1:100,000-1:120,000 live births. The frequency of HT1 in the Russian Federation is unknown. AIM: To estimate the spectrum of mutations in HT1 in several ethnic groups of the Russian Federation. MATERIALS AND METHODS: From 2004 to 2017, 43 patients were diagnosed with HT1. The analysis of amino acids and succinylacetone was performed using NeoGram Amino Acids and Acylcarnitines Tandem Mass Spectrometry Kit and a Sciex QTrap 3200 quadrupole tandem mass spectrometer. Bi-directional DNA sequence analysis was performed on PCR products using an ABI Prism 3500. RESULTS: In the Russian Federation, the most common mutation associated with HT1 (32.5% of all mutant alleles) is c.1025C>T (p.Pro342Leu), which is typical for the Chechen ethnic group. Patients of the Yakut, the Buryat, and the Nenets origins had a homozygous mutation c.1090G>C (p.Glu364Gln). High frequency of these ethnicity-specific mutations is most likely due to the founder effect. In patients from Central Russia, the splicing site mutations c.554-1G>T and c.1062+5G>A were the most prevalent, which is similar to the data obtained in the Eastern and Central Europe countries. CONCLUSION: There are ethnic specificities in the spectrum of mutations in the FAH gene in HT1. The Chechen Republic has one of the highest prevalence of HT1 in the world.