Background. The genetic etiology of hypertrophic cardiomyopathy (HCM) is complex and population-specific, yet Russian HCM patients remain understudied. Methods. Between 2015-2025, unrelated pediatric and adult HCM patients were genotyped in a single laboratory. Children were sequenced with a 404-gene panel and adults with a 17-gene panel. Genotype-phenotype correlations were assessed for carriers of the most frequent variant, MYBPC3 c.3697C>T, and compared with patients harboring other MYPBC3 variants. Haplotype analysis explored its potential founder effect. Results. The cohort comprised 315 children (mean age 11.7 years, 61% male; 127 infant-onset) and 3,409 adults (mean age 47.5 years, 58% male). Genotype-positive rates were 89% in children and 28% in adults. Sarcomeric and RASopathy variants accounted for 35% and 33% of infant-onset, 56% and 17% of childhood-onset, and 22% and 0.4% of adult-onset genotyped cases, respectively. The MYBPC3 c.3697C>T variant was identified in 83 patients (2.2%). Compared with controls (n = 85), carriers (n = 58) more often had left ventricular ejection fraction below 50% (9% vs. 1%, p = 0.038), left atrial dilation (76% vs. 47%, p = 0.001), and supraventricular arrythmias (45% vs. 25%, p = 0.027). Pediatric carriers showed no left ventricular outflow tract obstruction (0% vs. 29%, p = 0.024) and fewer conduction disturbances (13% vs. 48%, p = 0.029). Intervention rates and outcomes were similar across ages. Haplotype analysis was inconclusive for founder effect. Conclusions. The genetic spectrum of HCM in Russian population largely mirrors Western data. Within MYBPC3-associated HCM, the c.3697C>T variant is linked to a milder, nonobstructive pediatric phenotype and increased hypokinetic progression in adults but does not influence overall outcomes. Its high prevalence likely reflects a combination of founder and recurrent mutational events. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This study did not receive any funding ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Ethics committee/IRB of National Medical Research Center for Children Health gave ethical approval for this work. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors

Schimke immuno-osseous dysplasia (SIOD) is a hereditary autosomal-recessive multi-system disorder with early mortality. It has variable clinical presentations, mainly characterised by disproportional short stature, steroid-resistant nephrotic syndrome, spondyloepiphyseal dysplasia, and T-cell immunodeficiency. In the majority of cases, SIOD is caused by pathogenic sequence variants (PSVs) in the SMARCAL1 gene that encodes protein involved in chromatin remodelling. SIOD is an ultra-rare condition, with an incidence of ~1 per 1-3 million live births; data on its genetic and clinical features are scarce. We conducted a retrospective study of 21 paediatric patients with SIOD diagnosed in our centre during the years 2003-2023. The most common extra-renal clinical features were short stature, osseous dysplasia, multiple stigmas, and leukopenia. Proteinuria of varying severity was observed in 16 cases. The five-year overall survival rate (OS) was 89% (95% CI 77-100%), and the ten-year OS was 10%. Next-generation sequencing (NGS) revealed the following PSVs in SMARCAL1 in 19 patients: c.355_500del, c.2542G>T, c.2290C>T, c.2562del, c.2533_2534del, c.1582A>C, c.1933C>T, c.1010T>C, c.1736C>T, c.2070dup, c.2551A>T, c.2149_2150dup, c.939delC, and c.1451T>A; the most common was c.2542G>T, resulting in premature translation termination (p.E848*), and it was found in 14 patients either in a homozygous (four patients) or compound-heterozygous (10 patients) state. According to microsatellite analysis, it is a "founder mutation" in Russia.

Here, we present a unique case of the combination of two rare hereditary diseases—a familial form of dilated cardiomyopathy (DCM) and arterial calcification (AC)—in a 10-month-old boy. DCM was caused by a novel pathogenic nucleotide variant (NV) c.542G>T in the MYH7 gene, and AC was caused by biallelic nucleotide variants c.3421C>T and c.4015C>T in the ABCC6 gene. NVs were identified by the next-generation sequencing (NGS) of a broad panel of 404 genes potentially involved in cardiovascular disorders and subsequently validated by Sanger sequencing in the proband and his parents. Cardiologic examinations confirmed the familial nature of cardiomyopathy and the pathogenicity of variant c.542G>T in MYH7 gene. This case highlights the clinical utility of NGS in identifying complex co-existing hereditary conditions and emphasizes the need for the comprehensive genetic testing of patients with atypical clinical presentations.

Introduction. Bronchopulmonary dysplasia (BPD) is a complex disease with a significant genetic predisposition. The aim of the study was to determine genetic markers associated with the development of bronchopulmonary dysplasia in premature infants. Materials and methods. At Stage 1, whole exome sequencing followed by the bioinformatic analysis of one hundred samples was provided to evaluate the genetic variants. Sequencing data were compared with the data of the children without any congenital pulmonary diseases. At Stage 2, the obtained results were validated using real-time PCR. Further the genotyping of the control group (n = 70) was performed. The obtained frequencies of nucleotide variants were compared between the groups, as well as with general population data using the RUSeq database. Results. The prevalence of genetic variant rs12489516 in gene CPA3 was significantly higher in the control group of premature infants (p = 0.03; OR = 0.2; 95% CI: 0.02–0.94). Its presence in the genotype reduces the likelihood of developing BPD by 4.76 times. Moreover, statistically significant differences were also identified in the prevalence of rs45488997 in gene CCN2 (p = 0.023). This genetic variant was specific only for children with bronchopulmonary dysplasia. It was also identified that the prevalence of the nucleotide variant rs45488997 in the CCN2 gene was statistically more common among patients with bronchopulmonary dysplasia compared with the general population (p = 0.005). In addition, genetic variants rs5744174 in gene TLR5 and rs2476601 in gene PTPN22 were less frequently observed in the investigated group compared to the general population (p = 0.03 and p = 0.003, respectively). Conclusion. Identification of genetic markers together with clinical and laboratory data will contribute to the development of an effective predictive model for the calculation of the probability of BPD.

To evaluate clinical signs and symptoms of nephropathic cystinosis in adult patients.

Introduction. Cystic fibrosis (CF) is an autosomal recessive hereditary disease resulting from the presence of pathogenic nucleotide variants (NVs) in the CTFR gene, encoding a regulator of the transmembrane transport of chloride ions. CF is characterized by an impaired secretory function of the epithelial cells of exocrine glands and, as a consequence, a number of systemic progressive pathological changes in the functioning of the gastrointestinal tract, respiratory system, etc. CF might be accompanied by a number of comorbidities (CMs), including those leading to the development of mutual burden, affecting the diagnosis or choice of therapy. At the same time, of CMs repertoire in CF may vary in different ethnic groups and populations, especially geographically isolated ones. Thus, for more informed approach to the diagnosis and treatment of CF in certain ethnic groups and populations, it is necessary to determine the CMs repertoire characteristic of these groups. Materials and methods. The study included one hundred twenty five 2 months to 17 years and 11 months patients with a confirmed diagnosis of CF. The children were divided into groups according to ethnicity: residents of the Chechen Republic (71 patient), residents of the Karachay-Cherkess Republic (23 patients), residents of the Republic of Ingushetia (9 patients), the Republic of Dagestan (16 patients), the Republic of North Ossetia — Alania (6 patients). Results. The frequencies and spectrum of comorbidities (CMs) in CF children from ethnic groups living in the North Caucasus Federal District differ from those previously described for CF patients from other populations and ethnic groups. The most common CMs identified in this study are adenoid hypertrophy (n = 51; 40.8%), chronic gastritis (n = 47; 37.6%), lactase deficiency (n = 38; 30.4%), gastroesophageal reflux disease (n = 30; 24%), development retardation (n = 22; 17.6%), allergies of various origins (n = 21; 16.8%), and consequences of perinatal damage to the central nervous system (n = 11; 8.8%). Conclusion. For the early differential diagnosis of CMs and further clinical management of pediatric CF patients, it is necessary to implement an interdisciplinary approach using of medical genetic methods, as well as additional monitoring by several medical specialists. First and foremost, the decision on which medical specialists should be involved in a clinical management of such patients should be based on the CMs repertoire prevailing in a given population or ethnic group. When performing a clinical monitoring of the CF children from the ethnic groups living predominantly in the North Caucasus Federal District, it is advisable to choose the therapeutic approach that takes into account the ethnic-specific features of CMs, identified in our work.

Periodic syndrome associated with variants in the Tumor Necrosis Factor receptor gene (hereinafter referred to as TNFRSF1A gene) – Associated periodic syndrome (hereinafter referred to as TRAPS) – is an autoinflammatory genetic disease that often occurs under the "mask" of juvenile arthritis (JA), as well as other rheumatic diseases. Knowledge of phenotypic and genetic features of the periodic syndrome associated with variants in the Tumor Necrosis Factor receptor gene will allow timely verification of the diagnosis and initiation of pathogenetic therapy, thereby reducing the risk of patient disability, complications and improving prognosis. Objective. To identify the peculiarities of clinical and laboratory manifestations of periodic febrile syndrome associated with variants in the Tumor Necrosis Factor receptor (TNFRSF1A) gene. Patients and Methods. A comparative retrospective analysis of clinical and laboratory manifestations of the disease was performed in 66 patients hospitalized in the rheumatology department of the National Medical Research Center for Children's Health (FSAI NMRC for Children's Health", Ministry of Health of Russia Moscow) in the period from March 1, 2013 to August 31, 2022, with the diagnosis of juvenile idiopathic arthritis and febrile syndrome: 33/66 (50%) with variants in the TNFRSF1A gene detected by molecular genetic study, 33/66 (50%) without variants in the TNFRSF1A gene. Results. Due to the presence of febrile syndrome, all patients underwent molecular genetic study to identify variants in genes associated with the development of autoinflammatory disease. In 33/66 patients a large variety of variants in TNFRSF1A gene was detected, of which: in 4/33 (12%) – variants were classified as probably pathogenic (c.337_339del, p.Glu113del, c.792del, p.Lys265Serfs*87, c.374G>A, p.Cys125Tyr, c.184 T>A, p.Cys62Ser in heterozygous state), in 1/33 (3%) – as pathogenic (c.242G>T, p.Cys81Phe in heterozygous state), in 3/33 (9.1%) – as variants of uncertain significance (c.596T>C, p.Ile199Thr, c.472+6C>T, p.?, c.194-14G>A p.? in heterozygous state). The most frequent variant of uncertain significance with incomplete penetrance was c.362G>A, p.Arg121Gln in heterozygous state in 27/33 (82%) patients. Patients with variants in the TNFRSF1A gene (n = 33) were diagnosed with autoinflammatory disease, patients without variants in genes associated with AID- with systemic SA. At disease debut, 65/66 (98.5%) patients presented with fever, 55/66 (83.3%) with rash, and 43/66 (65.1%) with joint involvement. Patients with variants in the TNFRSF1A gene showed clinical manifestations that were absent in patients diagnosed with sJIA: attack-like fever (48.5%), abdominal pain (33.3%), gastrointestinal lesions (27.2%): Diarrhea with pathological impurities (6.1%), diarrhea without impurities (12.1%), vomiting (6.1%); eye lesions (uveitis and retinal angiopathy) (24.2%), chest pain (12.1%), hearing loss (9.1%), periorbital edema (9.1%), delay in psychoverbal development (6.1%), aseptic meningitis (3%) and hydrocephalus (3%). Similar symptoms that developed in patients with TNFRSF1A gene variants and sJIA were characterized by features for each disease: In sJIA, fever persisted for more than 7 days, the rash was patchy-papular in nature, and arthralgia was prevalent; in patients with TNFRSF1A gene variants, fever lasted less than 7 days, the rash had a smallspotted, large-spotted, vesicular character, the joint syndrome developed significantly more often than in sJIA (in 78.8% and 51.5%, respectively, p = 0.03) and was manifested by oligo- and polyarthritis. Conclusion. The presence of variants in the TNFRSF1A gene may be associated with a wide variety of clinical manifestations, therefore, all patients with febrile syndrome with suspected juvenile idiopathic arthritis, joint involvement in combination with rash and/or other manifestations should undergo a molecular genetic study to identify variants in the TNFRSF1A gene to verify the diagnosis of autoinflammatory disease at an early stage in order to initiate pathogenetic therapy and prevent the development of complications. Key words: autoinflammatory syndrome, recurrent syndrome associated with tumor necrosis factor receptor gene mutation, TRAPS, molecular genetic diagnosis, rheumatology, pediatrics, children

Introduction. Brain–lung–thyroid syndrome (BLTS, choreoathetosis and congenital hypothyroidism with or without pulmonary dysfunction) is an autosomal dominant disorder associated with mutations of the NKX2-1 gene. A triad of symptoms from three organs (brain, lungs, thyroid gland) is manifested in 50% of patients, in other cases there is an incomplete phenotype of the disease. The most common manifestations are neurological. The aim of the study was to provide genetic, clinical, laboratory, and instrumental characteristics in BLTS patients with a clinical and morphological assessment of the phenotype. Materials and methods. Ten children from 9 families with identified mutations in the NKX2-1 gene were observed. Methods used: genealogical, Sanger sequencing, clinical and morphological assessment of the phenotype, examination of thyroid hormone levels, CT, MRI of the brain, CT of the chest, lung biopsy. Results. The article presents the results of molecular genetic analysis, family history, age of manifestation and diagnosis. 9 out of 10 children had damage to the central nervous system, thyroid gland, lungs, and one child had a combination of neurological pathology and hypothyroidism. Neurological pathology was represented by benign hereditary chorea (2 children), delayed motor development (8), muscular hypotension (7), ataxia (5), choreoathetosis (1), clonuses (1), seizures (1), hyperkinesis (3); respiratory — respiratory distress syndrome (RDS) of newborns (6), chronic respiratory failure (5), interstitial lung disease (6), bronchial asthma (1), chronic pneumonitis of infants (1), bronchiectasis (1). There are presented changes in computed tomograms of the lungs and during preforming CT, MRI of the brain. Typical developmental microanomalia included a protruding forehead, a wide tip of the nose, elongated narrow palpebral fissure, deep-set eyes, hypertelorism of the eyes, large rotated low-lying auricles, conical fingers. Conclusion. A combination of congenital hypothyroidism, neonatal RDS, heart disease, neurological disorders (hypotension, ataxia, delayed motor development, chorea), craniofacial dysmorphia is the basis for a molecular genetic examination to exclude BLTS.

Zhu–Tokita–Takenouchi–Kim syndrome (ZTTK syndrome) is a rare autosomal dominant nuclear speckleopathy characterized by developmental delay, hypotonia, intellectual disability, facial dysmorphism in association with variable brain malformations, musculoskeletal abnormalities and ocular involvement. Currently, 87 cases of ZTTK syndrome have been described worldwide. The syndrome caused by mutations in the SON gene, located on the long arm of chromosome 21 (21q22.11). Nonsense and frameshift mutations have been described in the SON gene. Missense mutations, partial or whole gene deletions are less common.The aim of the work is to analyze the clinical picture and molecular genetic results of patients with confirmed ZTTK syndrome and compare them with data from foreign literature.We observed the one boy and two girls with ZTTK syndrome aged 13 months to 59 months, averaging about 38 months. DNA diagnostic was performed by next generation sequencing. All patients and all parents were confirmed by Sanger sequening. Three pathogenic variants were identified: c.5753_5756delTTAG (p.Val1918Glufs*87), c.1531del (p.Thr511Glnfs*9) and c.403delG (p.Glu135Asnfs*14). The first one was is most common, the other two are novel variants. Most patients had growth, motor and speech delay, seizures, hypotonia, congenital heart defects, urinary tract abnormalities and brain malformations. Comparative analysis of facial features in patients with ZTTK syndrome showed downslanting palpebral fissures, epicantal folds, broad or depressed nasal bridge, flared nares, smooth philtrum, thin upper lip and low set, rotated ears. The use of next generation sequencing as a first‑line test for research and diagnostic of ZTTK syndrome is advisable due to the pronounced clinical polymorphism.

Background. Primary ciliary dyskinesia (PCD) is an orphan disease, and diagnosis is difficult because there is no gold standard for diagnosis. Aim. Clinical, laboratory-instrumental, genetic characteristics of PCD in children. Materials and methods. From 2009 to 2024, 31 patients with a genetically confirmed diagnosis of PCD were observed as part of a multicenter, open-ended, descriptive pilot longitudinal study. Examination methods: clinical and anamnestic method; X-ray examination and computed tomography of the chest organs and paranasal sinuses, tracheobronchoscopy; sputum/aspirate cultures of the tracheobroncheal tree with determination of sensitivity to antibiotics; transmission electron microscopy, high-speed video microscopy of the ciliated epithelium, cytological examination of bronchoalveolar lavage; monitoring computer pulse oximetry, echocardiography, audiometry, spirometry with bronchodilator test. Results. Respiratory symptoms in the neonatal period have 80% of children with PCD, lateralization defects – 35%, congenital heart defects – 13%, bronchiectasis – 68%, purulent endobronchitis – 62%, year-round rhinitis – 84%, hearing loss, otitis – 65%. The average age of onset of symptoms was 1 [1; 1] weeks, and the verification of diagnosis was 6 [2,5; 8] years. The main pathogens of chronic respiratory infection with PCD are Haemophilus influenzae, Pseudomonas aeruginosa, Staphylococcus aureus. The most common cause of PCD was biallelic variants of the DNAH5 gene. Conclusion. The diagnosis of PCD should be based on the application of the maximum number of diagnostic tests.

Background: Cystic fibrosis (CF) is an autosomal recessive disease that occurs with a frequency of 1:1,500 to 1:5,000 newborns, according to the World Health Organization. In the Russian Federation, the average incidence of the disease is 1:10,000 newborns. The medical and social significance of this disease is associated with the early disability of patients, the need for long-term treatment and constant follow-up, as well as the heterogeneity of phenotypic manifestations, which in turn requires early diagnosis using molecular genetic methods. The aim of the study: To study the clinical and molecular genetic characteristics of children with CF from the Chechen and Karachay-Cherkess Republics. Materials and methods: The study included 237 patients with a confirmed diagnosis of CF. Molecular genetic diagnostics was performed using the method of mass parallel sequencing using a hybridization target panel that includes the entire CFTR gene. Sequencing was performed on the MiSeq platform. All causal nucleotide variants were validated using Sanger sequencing. Results: The most common amino acid variants of the CFTR gene in patients with CF from the Chechen Republic are: p.Y515* (94 alleles/78.3%), p.E92K (18 alleles/15%). The presence of variants p.Y515* and p.E92K in the heterozygous state in the genotype is more often a favorable prognostic factor for the absence of pancreatic lesion. The main distinctive clinical feature of these patients is the onset of the disease with manifestations of pseudo-Bartter syndrome. The major amino acid variant of the CFTR gene in patients with CF from the Karachay-Cherkess Republic is: p.W1282* (28 alleles/70%). The number of patients with pseudo-Bartter syndrome was 54.5%. In 90% of cases, in patients who are homo- and heterozygous according to p.W1282*, a severe degree of pancreatic insufficiency was noted. Conclusion: Patients with cystic fibrosis from the Chechen and Karachay-Cherkess Republics are a difficult category of patients, despite neonatal screening, and cystic fibrosis therapy developed and implemented. This is partly due to the peculiarities of the phenotype and the unique distribution of alleles and genotypes of the CFTR gene. The high number of homozygous variants of the CFTR gene in patients from the Chechen and Karachay-Cherkess Republics is probably due to monoethnic marital assortativity.

Barth syndrome (BS) is an orphan disease whose variability of clinical manifestations does not always allow its timely diagnosis, which in its turn reduces the quality of medical care and worsens the prognosis for outcomes. Currently there are some scientific publications in Russia on isolated cases of the disease and none of a kind dedicated to the long-term observation of patients with assessment of the clinical picture. The purpose of this research was to analyze the dynamics of clinical manifestations in children with BS. Materials and methods used: a cohort study included observation of 9 boys with BS in 2015-2022. Results: all patients with genetically confirmed BS were diagnosed with cardiomyopathy with non-compact myocardium, while a dilated remodeling phenotype was noted in 78% of cases. In 67% of children, against the background of complex drug therapy, a decrease in the size of the left ventricle with an increase in ejection fraction was recorded. Neutropenia was detected in 89% of patients, requiring the use of granulocyte colony-stimulating factor in two cases. Frequent detection of prolongation of the QT interval (78%) and ECG patterns simulating the phenomenon of pre-excitation against the background of intraventricular conduction disturbances, acceleration of AV conduction, secondary disturbances of repolarization processes (44%) without fixation of ventricular arrhythmias were noted. The severity of the condition was determined by a combination of severe heart failure, conduction disturbances and clinically significant neutropenia. Fatal outcomes were recorded in 2 children (22%) at the age of 8 months old and 3.5 years old against the background of progressive heart failure and sudden death, respectively. Conclusion: a comprehensive multidisciplinary approach and early diagnosis of BS have an impact on the outcome of the disease.

Thiamn-biotin dependent basal ganglia disease is a rare inherited disorder. The earliest possible diagnosis plays a crucial role in prevention of death or brain damage due to the severity of the disease. Neonatal screening is not adequate because of the extreme rarity of this disease. The demonstrated familial record showcases the need for selective screening in cases of a burdened familial anamneses in patients with undifferentiated encephalitic crises, including undifferentiated mitochondrial encephalopathies, and confirms the importance of the earliest possible start of metabolic therapy with thiamine and biotin in order to reaching the satisfactory compliance from the family. The severe importance of regular dispensary observation and testing coupled with the timely correction of treatment in such patients is shown as well.

Patients with pancreatic cancer (PC) showing mismatch repair (MMR) deficiency may benefit from immunotherapy. Microsatellite instability (MSI) is a hallmark of MMR deficiency (MMR-D). Here, we estimated the prevalence of MSI in PC, investigated germline and somatic mutations in the three MMR genes (MLH1, MSH2, and MSH6), and assessed the relationship between MMR genes mutations and MSI status in PC. Clinical specimens from PC patients were analyzed using targeted next-generation sequencing, including paired normal and tumor specimens from 155 patients, tumor-only specimens from 86 patients, and normal-only specimens from 379 patients. The MSI status of 235 PCs was assessed via PCR. Pathogenic/likely pathogenic (P/LP) germline variants in the MMR genes were identified in 1.1% of patients, while somatic variants were found in 2.6% of patients. No MSI-H tumors were detected. One patient carried two variants (P (VAF = 0.57) and LP (VAF = 0.25)) simultaneously; however, their germline/somatic status remains unknown due to the investigation focusing solely on the tumor and MSI analysis was not performed for this patient. MSI is rare in PC, even in tumors with MMR genes mutations. Our findings underscore the importance of assessing tumor MMR-D status in PC patients with confirmed Lynch syndrome when deciding whether to prescribe immunotherapy.

Introduction. Nephrocalcinosis (NC) is defined as the deposition of calcium oxalate or calcium phosphate in the intratubular lumen and/or kidney interstitium. Recent studies have reported that NC might be a specific sign of hereditary kidney diseases with various phenotypic manifestations. The rate of genetic mutation as a rule was higher in children with earlier onset and positive family history. Purpose. To study the causes, characterize the genotype and phenotype in Russian children with NC. Materials and methods. A single-center retrospective-prospective cohort study included 91 patient under the age of 18 years, 57 (62.6%) boys and 34 (37.4%) girls with bilateral NC. We analyzed the phenotype and kidney function in NC children classified into 3 groups according to etiology: 1) primary tubulopathies; 2) tubulopathies due to metabolic and endocrine disorders; 3) NC, unconfirmed by molecular genetic research. Results. Pathogenic nucleotide variants were identified in 51 (56%) children with a predominance in the genes CLCN5, CYP24A1, AGXT, HPRT1 described in patients with Dent disease (OMIM 300009), primary hyperoxaluria type 1 (OMIM 259900), idiopathic infantile hypercalcemia type 1 (OMIM 143880), Lesh–Nihan syndrome (OMIM 300322) respectively. The median age of detection of NC was 16 years, 4 [3.9; 52.2 months, among which 42 (46.1%) children were under the age of 1 year, 44 (48.4%) aged 1 to 10 years, 5 (5.5%) older than 10 years. Various bone deformities prevailed among the extrarenal manifestations (19 (20.4%)). Over 3 years of follow-up (n = 51) the average GFR changed from 102.5 ± 26.0 ml/min/1.73 m2 to 94.5 ± 21.9 ml/min/1.73 m2 (p = 0.002); over 5 years of follow-up (n = 31) from 104.7 ± 23.9 ml/min/1.73 m2 to 89.6 ± 25.1 ml/min/1.73 m2 (p = 0.002), that was statistically significant in the group of primary tubulopathies (p = 0.030; p = 0.002). At baseline, the average GFR value was lower in NC stages 2 and 3. Conclusion. Conducting a molecular genetic study in NC children, in addition to early diagnosis of diseases with variable renal prognosis and will also help to achieve effectiveness in the timely prescription of pathogenetic and symptomatic therapy.