Larysa N Sivitskaya

Advances in gene therapy and genome editing give hope that new treatments will soon be available for inherited eye diseases that together affect a significant proportion of the adult population. New solutions are needed to make genetic diagnosis fast and affordable. This is the first study of such a large group of patients with inherited retinal dystrophies (IRD) and inherited optic neuropathies (ION) in the Polish population. It is based on four years of diagnostic analysis using a broad, targeted NGS approach. The results include the most common pathogenic variants, as well as 91 novel causative variants, including frameshifts in the cumbersome RPGR ORF15 region. The high frequency of the ABCA4 complex haplotype p.(Leu541Pro;Ala1038Val) was confirmed. Additionally, a deletion of exons 22–24 in USH2A, probably specific to the Polish population, was uncovered as the most frequent copy number variation. The diagnostic yield of the broad NGS panel reached 64.3% and is comparable to the results reported for genetic studies of IRD and ION performed for other populations with more extensive WES or WGS methods. A combined approach to identify genetic causes of all known diseases manifesting in the posterior eye segment appears to be the optimal choice given the currently available treatment options and advanced clinical trials.

Purpose. To study the diagnostic value of cascade family screening and the spectrum of genetic variants in patients with familial and sporadic DCM, assess clinical outcomes and comparative analysis of 5-year event-free survival.Materials and methods. The study included 156 unrelated patients with verified DCM. All patients (aged 46 [34; 57] years; 125 (80%) male; LVEF 31 [24; 38]%; LV EDD 68 [61; 74] mm; follow-up period - 77 [59; 108] months) a complex of clinical and instrumental studies (ECG, ECHO, HM, MRI), cascade family screening with genetic testing (NGS+Sanger) and segregation analysis were performed.Results. Criteria for familial DCM were identified in 73 (46.8%) probands. The genetic cause of DCM was identified in 47 (64,4%) familial cases, while for sporadic form DCM pathogenic variants were detected in 19 (22,9%) patients. The dominant mutations were truncating variants in the titin gene (10,9%) and variants in the lamin A/C (LMNA) gene - 8,33%. As a result of the evaluation of cumulative event-free survival (Kaplan-Meier curves), LMNA carriers showed the poor 5-year prognosis for ventricular tachyarrhythmic events (x²=39.9; p=0,0001) and composite adverse outcomes (x²=12.1; p=0.001). Probands who had a familial DCM (log rang x²=38.5; p=0,0001) showed the worst prognosis and low cumulative survival when compared with patients of the sporadic DCM.Conclusion. Cascade clinical family screening and genetic testing in the DCM cohort increased the level of diagnosis of familial DCM from 4.5% to 46.8%. Associations of LMNA mutations with life-threatening tachyarrhythmias are defined as prognostically significant, that confirms the important role of genetic stratification of arrhythmic risk.

Danon disease (DD), a rare X-linked genetic illness with a poor prognosis, is caused by a mutation in the lysosome-associated membrane protein 2 gene (LAMP2). Three main clinical features of this pathology are cardiomyopathy, skeletal myopathy, and mental retardation. Most Danon disease mutations create premature stop codons resulting in the decrease or absence of LAMP2 protein. The present case reports the frameshift variant c.190_191delАС in the LAMP2 in the family with sudden cardiac death history and three members with cardiomyopathy. The presenting phenotype in a female proband with c.190_191delАС was isolated dilated cardiomyopathy in her thirties whereas in two males, DD presented as hypertrophic cardiomyopathy and mild skeletal myopathy since childhood. To examine the contribution of X-inactivation to cardiomyopathy onset we estimated the X-inactivation status in the heart tissue of the affected female. We observed the random pattern (66:34) with the proportion of cardiomyocytes expressing healthy LAMP2 allele reduced to 34%. Deletion c.190_191delАС has led to a complete loss of function LAMP2 due to a single copy of this gene in males. In a woman, cardiomyopathy developed because of both the LAMP2 mutation and a decrease in the expression of a healthy allele in the heart. Based on the strong association of truncating LAMP2 mutations with DD and phenotypes in affected members, the variant c.190_191delАС was classified as pathogenic.

Aim. To study and compare genotypic and phenotypic signs in patients with non-compaction cardiomyopathy (NCM) and dilated cardiomyopathy (DCM), to conduct a comparative analysis of clinical outcomes and 5-year cumulative survival of patients with NCM and DCM.Material and methods. The study included 144 unrelated patients with cardiomyopathy: NCM (n=74) and DCM (n=70). Mean age was 39 [30; 49] years (men, 96 (66,7%); left ventricular ejection fraction (LVEF) was 30,5 [24; 46]%. A comprehensive clinical examination included electrocardiography, Holter monitoring, echocardiography, cardiac magnetic resonance imaging, coronary angiography, DNA diagnostics (NGS+Sanger), cascade screening, and cosegregation analysis. To assess clinical outcomes, the NCM group was divided into 2 subtypes according to baseline LV systolic function (NCM/DCM phenotype — 50 individuals with LVEF ≤49%; and isolated NCM — 24 patients with LVEF ≥50%). The following adverse events were assessed as the composite endpoint: cardiovascular death, heart transplantation (HT), sustained ventricular tachycardia, ventricular fibrillation, successful cardiopulmonary resuscitation, cerebral thromboembolism. The follow-up period was 62 months.Results. Among patients with LVEF ≤49% at a 5-year follow-up, 37 (74,0%) of 50 patients with the NCM/DCM phenotype and 41 (58,6%) of 70 patients with DCM achieved composite endpoint. Out of 24 patients with NCM with LVEF ≥50% (median LVEF, 56 [51; 61]%), 2 (8,3%) patients achieved composite endpoint (χ²=28,8; p=0,001). In the NCM/DCM group with LVEF ≤49%, a higher level of pathogenic genetic variants (64% vs 41,4%/DCM vs 29,2%/NCM; χ²=11,4; p=0,003), cerebral thromboembolism (χ²=11,8; p=0,003) and HT (χ²=10,6; p=0,005). The results of the 5-year survival analysis (Kaplan-Meier) showed a worse prognosis for NCM with LVEF ≤49% compared with DCM (log rang: χ²=11,5; p=0,001) and isolated NCM (log rang: χ²=17,02; p=0,0001). In the overall cohort (n=144), gene-positivity was also associated with worse prognosis (log rang: χ²=5,38; p=0,02).Conclusion. In the present study, patients with dilated subtype of NCM showed a worse prognosis compared with DCM and isolated NCM. Heart failure progression and cerebral thromboembolism were the most common complications in patients with NCM/DCM.

Aim. To study the diagnostic significance of genetic testing in patients with dilated cardiomyopathy (DCM), identify predictors of life-threatening ventricular tachyarrhythmias (VTAs) and assess adverse clinical outcomes in different genetic groups.Material and methods. The study included 126 unrelated patients with verified DCM as follows: 70 (55,6%) probands with criteria for familial DCM and 56 (44,4%) individuals with a probable hereditary component. All patients (age, 43,1±11,3 years; men, 92 (73%); left ventricular ejection fraction, 30,6±8,43%; left ventricular enddiastolic diameter, 68,3±8,36 mm; follow-up period — median, 49 months) receive a complex of diagnostic investigations, including genetic screening using nextgeneration sequencing, followed by verification of variants by the Sanger method.Results. Pathogenic and likely pathogenic genetic variants were found in 61 (48,4%) of 126 patients with DCM. The dominant mutations were titin-truncating variants (TTNtvs), identified in 16 individuals (12,7%), and variants of lamin A/C (LMNA), identified in 13 probands (10,3%). Mutations in the other 19 genes were found in 32 (25,4%) patients. The following primary endpoints were assessed: sudden cardiac death (SCD), episodes of VTA (sustained ventricular tachycardia/ventricular fibrillation) and appropriate shocks of implanted cardiac resynchronization therapy (CRT)/cardioverter defibrillators (CVD) devices. As a result of ROC analysis, the following independent risk factors for SCD were identified: mutations in the LMNA gene (AUC, 0,760; p=0,0001) and non-sustained ventricular tachycardia (cut-off heart rate ≥161 bpm: AUC, 0,788; p=0,0001). When comparing the phenotypes and genotypes of DCM, TTNtv genotype was associated with a lower prevalence of complete left bundle branch block (χ²=7,46; p=0,024), a lower need for CRT/CVD implantation (χ²=5,70; p=0,017) and more rare episodes of sustained ventricular tachycardia/ventricular fibrillation (χ²=30,1; p=0,0001) compared with LMNA carriers. Kaplan-Meier analysis showed the worst prognosis in carriers of LMNA mutations both in relation to life-threatening VTA (log rang χ²=88,5; p=0,0001) and in achieving all unfavorable outcomes (χ²=27,8; p=0,0001) compared with groups of genenegative individuals, carriers of TTNtv and other genotypes.Conclusion. The phenotypes of DCM with TTNtv did not significantly differ in the incidence of VTAs and adverse outcomes compared with the gene-negative group and other genotypes (with the exception of LMNA). The contribution of the associations of LMNA mutations with VTAs on prognosis was confirmed, which shows the important role of LMNA genotype diagnosis for SCD risk stratification in patients with DCM.

NGS technologies have transformed clinical diagnostics and broadly used from neonatal emergencies to adult conditions where the diagnosis cannot be made based on clinical symptoms. Autoimmune diseases reveal complicate molecular background and traditional methods could not fully capture them. Certainly, NGS technologies meet the needs of modern exploratory research, diagnostic and pharmacotherapy. Therefore, the main purpose of this review was to briefly present the application of NGS technology used in recent years in the understanding of autoimmune diseases paying particular attention to autoimmune connective tissue diseases. The main issues are presented in four parts: (a) panels, whole-genome and -exome sequencing (WGS and WES) in diagnostic, (b) Human leukocyte antigens (HLA) as a diagnostic tool, (c) RNAseq, (d) microRNA and (f) microbiome. Although all these areas of research are extensive, it seems that epigenetic impact on the development of systemic autoimmune diseases will set trends for future studies on this area.

Methotrexate (MTX) is the first-line therapy for rheumatoid arthritis. Nevertheless, MTX resistance is quite a common issue in clinical practice. There are some premises that aryl hydrocarbon receptor (AhR) gene battery may take part in MTX metabolism. In the present retrospective study, we analyzed genes expression of AHR genes battery associated with MTX metabolism in whole blood of RA patients with good and poor response to MTX treatment. Additionally, sequencing, genotyping and bioinformatics analysis of AHR repressor gene (AHRR) c.565C > G (rs2292596) and c.1933G > C (rs34453673) have been performed. Theoretically, both changes may have an impact on H3K36me3 and H3K27me3. Evolutionary analysis revealed that rs2292596 may be possibly damaging. Allele G in rs2292596 and DAS28 seems to be associated with a higher risk of poor response to MTX treatment in RA. RA patients with poor response to MTX treatment revealed upregulated AhR and SLC19A1 mRNA level. Treatment with IL-6 inhibitor may be helpful to overcome the low-dose MTX resistance. Analysis of gene expression revealed possible another cause of poor response to MTX treatment which is different from that observed in the case of acute lymphoblastic leukemia.

В работе представлены результаты поиска патогенных факторов, обусловливающих развитие лекарственно-устойчивой эпилепсии у детей. Поиск выполняли методом массового параллельного секвенирования образцов ДНК. У пяти пациентов (42% исследуемой группы) обнаружены и верифицированы патогенные и вероятно патогенные варианты нуклеотидной последовательности в генах, связанных с функционированием ионных каналов, синаптической передачей, регуляцией экспрессии генов и аутофагией. Во всех случаях определено de novo происхождение мутаций.

Некомпактная кардиомиопатия. Часть II: ограничения визуализирующих методик и генетического скрининга, клинические наблюдения

Atrial cardiomyopathy (ACM) is a relatively common but clinically underestimated disorder, which is characterized by an increased atrial size and dysfunction. Previously, ACM was considered a primary disorder, but in 2016 this concept was revised by European Heart Rhythm Association (EHRA) working group with inclusion of secondary atrial remodeling. The EHRA document details aspects of atrial anatomy and pathophysiology, proposes definitions of ACM, histological classification, outlines the molecular mechanisms of atrial arrhythmia and the problems of personalized treatment and optimization of indications for catheter ablation.Practical application of the proposed ACM classification system, the clinical significance of novel ACM concept and the potential role of this information for a practitioner are presented in this article. Two clinical cases of ACM with “primary” (familial form of ACM due to NPPA gene mutation with primary defect in atrial structure and function) and “secondary” atrial remodeling (ACM caused by a longterm supraventricular tachyarrhythmias due to SCN1B gene mutation).