Genetic risk factors for dilated cardiomyopathy

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

Non-compaction and dilated cardiomyopathy: genotypic, phenotypic and prognostic differences

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

The Predicted Secretome of the Plant Pathogenic Fungus Fusarium graminearum: A Refined Comparative Analysis

The fungus Fusarium graminearum forms an intimate association with the host species wheat whilst infecting the floral tissues at anthesis. During the prolonged latent period of infection, extracellular communication between live pathogen and host cells must occur, implying a role for secreted fungal proteins. The wheat cells in contact with fungal hyphae subsequently die and intracellular hyphal colonisation results in the development of visible disease symptoms. Since the original genome annotation analysis was done in 2007, which predicted the secretome using TargetP, the F. graminearum gene call has changed considerably through the combined efforts of the BROAD and MIPS institutes. As a result of the modifications to the genome and the recent findings that suggested a role for secreted proteins in virulence, the F. graminearum secretome was revisited. In the current study, a refined F. graminearum secretome was predicted by combining several bioinformatic approaches. This strategy increased the probability of identifying truly secreted proteins. A secretome of 574 proteins was predicted of which 99% was supported by transcriptional evidence. The function of the annotated and unannotated secreted proteins was explored. The potential role(s) of the annotated proteins including, putative enzymes, phytotoxins and antifungals are discussed. Characterisation of the unannotated proteins included the analysis of Pfam domains and features associated with known fungal effectors, for example, small size, cysteine-rich and containing internal amino acid repeats. A comprehensive comparative genomic analysis involving 57 fungal and oomycete genomes revealed that only a small number of the predicted F. graminearum secreted proteins can be considered to be either species or sequenced strain specific

Dilated cardiomyopathy: reconceptualization of the problem

Dilated cardiomyopathy (DCM) is a complex, etiologically heterogeneous myocardial disease, which is one of the main causes of heart failure and heart transplantation. In 2016, experts from the European working group proposed a new definition of cardiomyopathy, which includes intermediate variants with a change in phenotype in carriers of mutations from subclinical form to the full manifestations of the disease. The classification of DCM was supplemented with intermediate phenotypes with the inclusion of a hypokinetic form with reduced contractile function without ventricular dilatation and variants with predominant dilation or arrhythmogenicity. Pathological architectonics of DCM consists of many genetic determinants that interact with numerous environmental factors. Clinical manifestations depend not only on the malignancy and penetrance of the gene mutation, but also on a number of other causes — epigenomic factors, age, toxic effects, environmental aggressiveness, pregnancy, and the effects of other acquired diseases. The article summarizes the current epidemiological data and ideas about specific molecular changes with an unfavorable prognosis. For clarity, we present clinical observations of familial DCM with mutations in the RBM20 and LMNA genes

Non-compaction cardiomyopathy. Part II: limitations of imaging techniques and genetic screening, clinical observations

Improvement of high-tech methods of cardiac imaging and new generation sequencing with their introduction into widespread practice has significantly expanded the potential of diagnosis of rare cardiomyopathies. Modern imaging methods make it easy to reveal the myocardial non-compaction. However, in clinical practice, significant difficulties remain in the differentiation of normal/borderline patterns of increased ventricular trabecularity, morphology of myocardial noncompaction and non-compaction cardiomyopathy (NCM). After three decades of research, verifying the NCM is still a major clinical challenge. A key aspect of this problem is the lack of generally accepted recommendations on the diagnostic criteria for NCM and low number of long-term multicenter studies with segregation analysis on familial NCMs. A promising solution is the development of a multistep algorithm for the diagnosis of NCM with the integration of familial, morphological, genetic and clinical data.The article presents a brief literary review on NCM diagnosis with a discussion of own research and comparative characteristics of clinical and genetic data. To confirm the clinical and molecular heterogeneity of NCM, there are brief clinical observations of mixed phenotypes with a detailed presentation of overlap NCMs in the MOGE(S) classification

A paradigm shift in the concept of arrhythmogenic cardiomyopathy: expanding the clinical and genetic spectrum, new diagnostic criteria for left ventricular phenotypes

Recent multicenter studies using high-tech cardiac imaging and novel translational technologies have shown that cardiac fibrofatty replacement, characteristic of arrhythmogenic cardiomyopathy (ACM), is observed in both ventricles; left ventricular (LV) involvement may be minimal, on par with the right ventricle (RV), or dominant. In 2019, the Heart Rhythm Society (HRS) proposed a new approach to the assessment of arrhythmic and genetic diseases with the inclusion of new phenotypes — left-dominant ACM and biventricular ACM. In 2020, to improve the diagnosis of left ventricular phenotypes, European experts revised ACM criteria (based on the 2010 ITF criteria), which are called the Padua criteria.The presented article highlights the clinical and genetic aspects of the new concept and the difficulties in ACM diagnosis, the practical experience of using new diagnostic algorithm. To help practitioners, step-by-step differential diagnosis and risk stratification of right and left ventricular phenotypes are presented using clinical examples (leftdominant ACM with a pathogenic variant in the LMNA gene; right-dominant ACM associated with a desmoplakin gene mutation, with predominant RV and moderate LV involvement; and an isolated RV ACM associated with a mutation in the plakophilin 2 gene)

Non-compaction cardiomyopathy. Part I: clinical and genetic heterogeneity and predictors of unfavorable prognosis

Non-compaction cardiomyopathy (NCM) is a rare heart disease characterized by a two-layered ventricular wall, comprising a thinner compact epicardial layer and an inner non-compacted layer. However, only structural and morphological data without a thorough clinical assessment does not determine the NCM (regardless of the diagnostic criterion used).Aim. To study the NCM-related genes, phenotypic and genetic correlations, predictors of life-threatening ventricular tachyarrhythmias (VTA) and adverse clinical outcomes.Material and methods. Of 93 individuals with identified morphological criteria of NCM (median follow-up, 5 years), the study included 60 unrelated patients (38,5±13,8 years of age; men, 33 (55%); left ventricular ejection fraction (LVEF), 42,1±12,9%) with clinical verification of NCM (>1 obligate phenotypic trait). Adverse cardiovascular events were taken as the composite end point: life-threatening VTA, death, heart transplantation.Results. Pathogenic (or probably pathogenic) mutations were detected in 33 (55%) patients with NCM. The most common variants (57,9%) were identified in the sarcomere protein genes (TTN, MYBPC3, MYH7); digenic mutations were found in 21,6% of patients. Digenic mutations were associated with low LVEF and the highest risk of systolic dysfunction (OR, 38; 95% CI, 4,74-305; p=0,0001). Multivariate regression provided a predictive model (R=0,90; R2=0,81; F (5,41) =34,8; p<0,0001) and independent predictors of adverse clinical outcomes of NCM (genetic cause of the disease (pathogenic mutation), LV systolic dysfunction, myocardial fibrosis in 2 or more ventricular segments, and QRS prolongation. Regression and ROC-analysis identified electrical predictors of life-threatening VTA (fragmented QRS, QT prolongation, spatial QRS-T angle increase) and morphofunctional markers (myocardial fibrosis, systolic dysfunction).Conclusion. The study revealed a significant clinical and genetic heterogeneity of NCM with predominant mutations in the sarcomeric protein genes and determined the criteria for identification and prognosis of NCM

Population structure and diversity of the pathogenic fungus Aspergillus fumigatus isolated from different sources and geographic origins

Fifty-five clinical and environmental Aspergillus fumigatus isolates from Mexico, Argentina, France and Peru were analyzed to determine their genetic variability, reproductive system and level of differentiation using amplified fragment length polymorphism markers. The level of genetic variability was assessed by measuring the percentage of polymorphic loci, number of effective alleles, expected heterozygocity and by performing an association index test (I A). The degree of genetic differentiation and variation was determined using analysis of molecular variance at three levels. Using the paired genetic distances, a dendrogram was built to detect the genetic relationship among alleles. Finally, a network of haplotypes was constructed to determine the geographic relationship among them. The results indicate that the clinical isolates have greater genetic variability than the environmental isolates. The I A of the clinical and environmental isolates suggests a recombining population structure. The genetic differentiation among isolates and the dendrogram suggest that the groups of isolates are different. The network of haplotypes demonstrates that the majority of the isolates are grouped according to geographic origin

Complete genome sequence of Sporisorium scitamineum and biotrophic interaction transcriptome with sugarcane

Sporisorium scitamineum is a biotrophic fungus responsible for the sugarcane smut, a worldwide spread disease. This study provides the complete sequence of individual chromosomes of S. scitamineum from telomere to telomere achieved by a combination of PacBio long reads and Illumina short reads sequence data, as well as a draft sequence of a second fungal strain. Comparative analysis to previous available sequences of another strain detected few polymorphisms among the three genomes. The novel complete sequence described herein allowed us to identify and annotate extended subtelomeric regions, repetitive elements and the mitochondrial DNA sequence. The genome comprises 19,979,571 bases, 6,677 genes encoding proteins, 111 tRNAs and 3 assembled copies of rDNA, out of our estimated number of copies as 130. Chromosomal reorganizations were detected when comparing to sequences of S. reilianum, the closest smut relative, potentially influenced by repeats of transposable elements. Repetitive elements may have also directed the linkage of the two mating-type loci. The fungal transcriptome profiling from in vitro and from interaction with sugarcane at two time points (early infection and whip emergence) revealed that 13.5% of the genes were differentially expressed in planta and particular to each developmental stage.Among them are plant cell wall degrading enzymes, proteases, lipases, chitin modification and lignin degradation enzymes, sugar transporters and transcriptional factors. The fungus also modulates transcription of genes related to surviving against reactive oxygen species and other toxic metabolites produced by the plant. Previously described effectors in smut/plant interactions were detected but some new candidates are proposed. Ten genomic islands harboring some of the candidate genes unique to S. scitamineum were expressed only in planta. RNAseq data was also used to reassure gene predictions