Background: Cardiomyopathies in children are serious, continuously progressing myocardium diseases which are characterized by a variety of the causes, symptoms, implications, and high lethality. More than 400 genes that can cause hereditary heart and vessels diseases are described in scientific literature. The application of a high-performance method of massive parallel sequencing allows to conduct the investigation of genome extended targeted areas revealing the variants and analyzing them (bioinformatics) for pathogenicity.Aims: Identification of a genetic etiology of hereditary cardiomyopathies development in children’s population of the Russian Federation.Materials and methods: The research included 103 patients with various phenotypes of cardiomyopathies aged from 3 months up to 17 years 9 months who at the moment of examination were observed in the cardiology department and the department of recovery treatment with cardiovascular diseases in the NMRCCH. All patients were performed massive parallel sequencing analyzing the targeted areas of 404 genes which mutations lead to the development of heart and vessels hereditary diseases.Results: The diagnostic algorithm based on the method of a massive parallel sequencing was developed. 176 258 minor options were identified in the explored target areas of genome of 103 patients. An average number of the revealed nucleotide replacements different from the reference sequence was 1711. We observed that about 40% of all variants founded by our means were found in MYH7, MYBPC3, TTN, MYH6, SCN5A, DSC2 and TPM1 genes. Bioinformatics analysis allowed revealing 68 novel genome variants associated with cardiomyopathy development. The reliable association of carriage of pathogenic option in MYBPC3 gene with development of hypertrophic cardiomyopathy in the Russian children was found.Conclusions: The application of the offered algorithm allowed establishing laboratory diagnoses to 99 (96.1%) patients out from 103 investigated subjects including the syndromal and non-syndromal forms of heart and vessels hereditary diseases which showed a cardiomyopathy phenotype.

MiRNA expression over different time periods (24 and 48 h) using the quantitative RT-PCR and deep sequencing has been evaluated in a model of photochemically induced thrombosis. A combination of two approaches allowed us to determine the miRNA expression patterns caused by ischemia. Nine miRNAs, including let-7f-5p, miR-221-3p, miR-21-5p, miR-30c-5p, miR-30a-3p, miR-223-3p, miR-23a-3p, miR-22-5p, and miR-99a-5p, were differentially expressed in brain tissue and leukocytes of rats 48 h after onset of ischemia. In addition, six miRNAs were differentially expressed in the brain tissue and blood plasma of rats 24 h after exposure, among which miR-145-3p and miR-375-3p were downregulated and miR-19a-3p, miR-92a-3p, miR-188-5p, and miR-532-5p were upregulated. In our opinion, miR-188-5p and miR-532-5p may be considered to be new potential markers of ischemic injury. The level of miRNA expression tended to increase 48 h after the onset of ischemia in brain tissue and leukocytes, which reflects not only the local response in brain tissue due to inflammation, vascular endothelial dysfunction, and disorders of the permeability of the blood–brain barrier, but also the systemic response of the organism to multifactor molecular processes induced by ischemic injury.

(1) Hypophosphatasia (HPP) is a rare inherited disease caused by mutations (pathogenic variants) in the ALPL gene which encodes tissue-nonspecific alkaline phosphatase (TNSALP). HPP is characterized by impaired bone mineral metabolism due to the low enzymatic activity of TNSALP. Knowledge about the structure of the gene and the features and functions of various ALPL gene variants, taking into account population specificity, gives an understanding of the hereditary nature of the disease, and contributes to the diagnosis, prevention, and treatment of the disease. The purpose of the study was to describe the spectrum and analyze the functional features of the ALPL gene variants, considering various HPP subtypes and clinical symptoms in Russian children. (2) From 2014–2021, the study included the blood samples obtained from 1612 patients with reduced alkaline phosphatase activity. The patients underwent an examination with an assessment of their clinical symptoms and biochemical levels of TNSALP. DNA was isolated from dried blood spots (DBSs) or blood from the patients to search for mutations in the exons of the ALPL gene using Sanger sequencing. The PCR products were sequenced using a reagent BigDye Terminator 3.1 kit (Applied Biosystems). Statistical analysis was performed using the GraphPad Prism 8.01 software. (3) The most common clinical symptoms in Russian patients with HPP and two of its variants (n = 22) were bone disorders (75%), hypomyotonia (50%), and respiratory failure (50%). The heterozygous carriage of the causal variants of the ALPL gene was detected in 225 patients. A total of 2 variants were found in 27 patients. In this group (n = 27), we identified 28 unique variants of the ALPL gene, of which 75.0% were missense, 17.9% were frameshift, 3.6% were splicing variants, and 3.6% were duplications. A total of 39.3% (11/28) of the variants were pathogenic, with two variants being probably pathogenic, and 15 variants had unknown clinical significance (VUS). Among the VUS group, 28.6% of the variants (7/28) were discovered by us for the first time. The most common variants were c.571G > A (p.Glu191Lys) and c.1171del (Arg391Valfs*12), with frequencies of 48.2% (13/28) and 11% (3/28), respectively. It was found that the frequency of nonsense variants of the ALPL gene was higher (p < 0.0001) in patients with the perinatal form compared to the infantile and childhood forms of HPP. Additionally, the number of homozygotes in patients with the perinatal form exceeded (p < 0.01) the frequencies of these genotypes in children with infantile and childhood forms of HPP. On the contrary, the frequencies of the compound-heterozygous and heterozygous genotypes were higher (p < 0.01) in patients with infantile childhood HPP than in perinatal HPP. In the perinatal form, residual TNSALP activity was lower (p < 0.0005) in comparison to the infantile and childhood (p < 0.05) forms of HPP. At the same time, patients with the heterozygous and compound-heterozygous genotypes (mainly missense variants) of the ALPL gene had greater residual activity (of the TNSALP protein) regarding those homozygous patients who were carriers of the nonsense variants (deletions and duplications) of the ALPL gene. Residual TNSALP activity was lower (p < 0.0001) in patients with pathogenic variants encoding the amino acids from the active site and the calcium and crown domains in comparison with the nonspecific region of the protein.

MiRNA expression over different time periods (24 and 48 h) using the quantitative RT-PCR and deep sequencing has been evaluated in a model of photochemically induced thrombosis. A combination of two approaches allowed us to determine the miRNA expression patterns caused by ischemia. Nine miRNAs, including let-7f-5p, miR-221-3p, miR-21-5p, miR-30c-5p, miR-30a-3p, miR-223-3p, miR-23a-3p, miR-22-5p, and miR-99a-5p, were differentially expressed in brain tissue and leukocytes of rats 48 h after onset of ischemia. In addition, six miRNAs were differentially expressed in the brain tissue and blood plasma of rats 24 h after exposure, among which miR-145-3p and miR-375-3p were downregulated and miR-19a-3p, miR-92a-3p, miR-188-5p, and miR-532-5p were upregulated. In our opinion, miR-188-5p and miR-532-5p may be considered to be new potential markers of ischemic injury. The level of miRNA expression tended to increase 48 h after the onset of ischemia in brain tissue and leukocytes, which reflects not only the local response in brain tissue due to inflammation, vascular endothelial dysfunction, and disorders of the permeability of the blood-brain barrier, but also the systemic response of the organism to multifactor molecular processes induced by ischemic injury.

Background: Fabry disease (FD) is a rare hereditary multisystem disease caused by variants of the GLA gene. Determination of GLA gene variants and identification of genotype–phenotype correlations allow us to explain the features of FD associated with predominant damage of one or another system, both in the classical and atypical forms of FD, as well as in cases with late manifestation and involvement of one of the systems. Methods: The study included 293 Russian patients with pathogenic variants of the GLA gene, which were identified as a result of various selective screening programs. Screening was carried out for 48,428 high-risk patients using a two-step diagnostic algorithm, including the determination of the concentration of the biomarker lyso-Gb3 as a first-tier test. Screening of atypical FD among patients with HCM was carried out via high-throughput sequencing in another 2427 patients. Results: 102 (0.20%) cases of FD were identified among unrelated patients as a result of the study of 50,855 patients. Molecular genetic testing allowed us to reveal the spectrum and frequencies of 104 different pathogenic variants of the GLA gene in 293 examined patients from 133 families. The spectrum and frequencies of clinical manifestations in patients with FD, including 20 pediatric patients, were described. Correlations between the concentration of the lyso-Gb3 biomarker and the type of pathogenic variants of the GLA gene have been established. Variants identified in patients with early stroke were described, and the association of certain variants with the development of stroke was established. Conclusions: The results of a large-scale selective FD screening, as well as clinical and molecular genetic features, in a cohort of 293 Russian patients with FD are described.

The pathogenic variants of genes encoding proteins, participating in the formation and functioning of epidermis and dermo-epidermal junctions, create a large variety of clinical phenotypes from: small localized to severe generalized dermatitis, as well as early, or even, prenatal death due to extensive epidermis loss. The diagnostic panel in this study was developed for the purposes of identifying these pathogenic genetic variants in 268 Russian children, who possessed the epidermolysis bullosa symptom complex in a selection of 247 families. This panel included the targeted areas of 33 genes, which are genetic variants that can lead to the development of the phenotype mentioned above. The usage of next generation sequencing allowed the revelation of 192 various altered alleles (of which 109 alleles were novel, i.e., had not been described previously). In addition, it allowed the definition of the genetic variants that are both typical for most of the examined children and for the separate ethnic groups inhabiting modern Russia. We found that the most characteristic mutations for the Dargin and Chechen ethnic groups are the c.3577del deletion in the COL7A1 gene and the c.2488G>A missense mutation in the COL17A1 gene, respectively. In addition, the study of haplotypes of microsatellite markers, which we managed to conduct in the Dargin population, confirmed the presence of the founder effect.