Dilated Cardiomyopathy: New Variant in the Filamin-C Gene.
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ABSTRACT:
SUBMITTER: Frasson MZ
PROVIDER: S-EPMC8291900 | biostudies-literature | 2021 Jul
REPOSITORIES: biostudies-literature
Publications
Dilated Cardiomyopathy: New Variant in the Filamin-C Gene.
Frasson Murilo Zomer MZ Jaeger Cristiano Pederneiras CP
Arquivos brasileiros de cardiologia 20210701 1 suppl 1
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Project description:In the vast majority of pediatric patients with dilated cardiomyopathy, the specific etiology is unknown. Studies on families with dilated cardiomyopathy have exemplified the role of genetic factors in cardiomyopathy etiology. In this study, we applied whole-exome sequencing to members of a non-consanguineous family affected by a previously unreported congenital dilated cardiomyopathy syndrome necessitating early-onset heart transplant. Exome analysis identified compound heterozygous variants in the FLNC gene. Histological analysis of the cardiac muscle demonstrated marked sarcomeric and myofibrillar abnormalities, and immunohistochemical staining demonstrated the presence of Filamin C aggregates in cardiac myocytes. We conclude that biallelic variants in FLNC can cause congenital dilated cardiomyopathy. As the associated clinical features of affected patients are mild, and can be easily overlooked, testing for FLNC should be considered in children presenting with dilated cardiomyopathy.
| S-EPMC5117915 | biostudies-literature
Project description:Three cases of delated cardiomyopathy (DCM) with conduction defects (OMIM 115200), limb girdle muscular dystrophy 1B (OMIM 159001) and autosomal dominant Emery-Dreifuss muscular dystrophy 2 (OMIM 181350), all associated with different LMNA mutations are presented. Three heterozygous missense mutations were identified in unrelated patients - p.W520R (c.1558T > C), p.T528R (с.1583С > G) and p.R190P (c.569G > C). We consider these variants as pathogenic, leading to isolated DCM with conduction defects or syndromic DCM forms with limb-girdle muscular dystrophy and Emery-Dreifuss muscular dystrophy. The mutations were not detected in the ethnically matched control group and publicly available population databases. Their de novo occurrence led to the development of the disease that was not previously detected in the extended families. Mutations at the same codons associated with laminopathies have been already reported. Differences in the clinical phenotype for p.R190P and p.T528R carrier patients are shown and compared to previous reports.
| S-EPMC5953234 | biostudies-literature
Project description:Mutations in the LMNA gene are a common cause (6-8%) of dilated cardiomyopathy (DCM) leading to heart failure, a growing health care problem worldwide. The premature aging disease Hutchinson-Gilford syndrome (HGPS) is also caused by defined mutations in the LMNA gene resulting in activation of a cryptic splice donor site leading to a defective truncated prelamin A protein called progerin. Low levels of progerin are expressed in healthy individuals associated with ageing. Here, we aimed to address the role of progerin in dilated cardiomyopathy.mRNA expression of progerin was analyzed in heart tissue of DCM (n = 15) and non-failing hearts (n = 10) as control and in blood samples from patients with DCM (n = 56) and healthy controls (n = 10). Sequencing confirmed the expression of progerin mRNA in the human heart. Progerin mRNA levels derived from DCM hearts were significantly upregulated compared to controls (1.27 ± 0.42 vs. 0.81 ± 0.24; p = 0.005). In contrast, progerin mRNA levels in whole blood cells were not significantly different in DCM patients compared to controls. Linear regression analyses revealed that progerin mRNA in the heart is significantly negatively correlated to ejection fraction (r = -0.567, p = 0.003) and positively correlated to left ventricular enddiastolic diameter (r = 0.551, p = 0.004) but not with age of the heart per se. Progerin mRNA levels were not influenced by inflammation in DCM hearts. Immunohistochemistry and Immunofluorescence analysis confirmed increased expression of progerin protein in cell nuclei of DCM hearts associated with increased TUNEL+ apoptotic cells.Our data suggest that progerin is upregulated in human DCM hearts and strongly correlates with left ventricular remodeling. Progerin might be involved in progression of heart failure and myocardial aging.
| S-EPMC5922532 | biostudies-other
Project description:Dilated cardiomyopathy (DCM) in infants and children can be partially explained by genetic cause but the catalogue of known genes is limited. We reviewed our database of 41 cases diagnosed with DCM before 18 years of age who underwent detailed clinical and genetic evaluation, and summarize here the evidence for mutations causing DCM in these cases from 15 genes (PSEN1, PSEN2, CSRP3, LBD3, MYH7, SCN5A, TCAP, TNNT2, LMNA, MYBPC3, MYH6, TNNC1, TNNI3, TPM1, and RBM20). Thirty-five of the 41 pediatric cases had relatives with adult-onset DCM. More males (66%) were found among children diagnosed after 1 year of age with DCM. Nineteen mutations in 9 genes were identified among 15 out of 41 patients; 3 patients (diagnosed at ages 2 weeks, 9 and 13 years) had multiple mutations. Of the 19 mutations identified in 12 families, mutations in TPM1 (32%) and TNNT2 (21%) were the most commonly found. Of the 6 patients diagnosed before 1 year of age, 3 had mutations in TPM1 (including a set of identical twins), 1 in TNNT2, 1 in MYH7, and 1 with multiple mutations (MYH7 and TNNC1). Most DCM was accompanied by advanced heart failure and need for cardiac transplantation. We conclude that in some cases pediatric DCM has a genetic basis, which is complicated by allelic and locus heterogeneity as seen in adult-onset DCM. We suggest that future prospective comprehensive family-based genetic studies of pediatric DCM are indicated to further define mutation frequencies in known genes and to discover novel genetic cause.
| S-EPMC3072577 | biostudies-literature
Project description:Dilated cardiomyopathy (DCM) is a life-threatening form of heart disease that is typically characterized by progressive thinning of the ventricular walls, chamber dilation, and systolic dysfunction. Multiple mutations in the gene encoding filamin C (FLNC), an actin-binding cytoskeletal protein in cardiomyocytes, have been found in patients with DCM. However, the mechanisms that lead to contractile impairment and DCM in patients with FLNC variants are poorly understood. To determine how FLNC regulates systolic force transmission and DCM remodeling, we used an inducible, cardiac-specific FLNC-knockout (icKO) model to produce a rapid onset of DCM in adult mice. Loss of FLNC reduced systolic force development in single cardiomyocytes and isolated papillary muscles but did not affect twitch kinetics or calcium transients. Electron and immunofluorescence microscopy showed significant defects in Z-disk alignment in icKO mice and altered myofilament lattice geometry. Moreover, a loss of FLNC induces a softening myocyte cortex and structural adaptations at the subcellular level that contribute to disrupted longitudinal force production during contraction. Spatially explicit computational models showed that these structural defects could be explained by a loss of inter-myofibril elastic coupling at the Z-disk. Our work identifies FLNC as a key regulator of the multiscale ultrastructure of cardiomyocytes and therefore plays an important role in maintaining systolic mechanotransmission pathways, the dysfunction of which may be key in driving progressive DCM.
| S-EPMC8779483 | biostudies-literature
Project description:Dilated cardiomyopathy (DCM) is one of the most common cardiac phenotypes caused by mutations of lamin A/C (LMNA) gene in humans. In our study, a cohort of 57 patients who underwent heart transplant for dilated cardiomyopathy was screened for variants in LMNA. We identified a synonymous variant c.936G>A in the last nucleotide of exon 5 of LMNA in a DCM family. Clinically, the LMNA variant carriers presented with severe familial DCM, conduction disease, and high creatine-kinase level. The LMNA c.936G>A variant is novel and has not been reported in current genetic variant databases. Sanger sequencing results showed the presence of LMNA c.936G>A variant in the genomic DNA but not in the cDNA derived from one family member's heart tissue. Real-time quantitative polymerase chain reaction showed significantly lower LMNA mRNA levels in the patient's heart compared to the controls, suggesting that the c.936G>A LMNA variant resulted in reduced mRNA and possibly lower protein expression of LMNA. These findings expand the understanding on the association between synonymous variant of LMNA and the molecular pathogenesis in DCM patients.
| S-EPMC8758524 | biostudies-literature
Project description: Not available
| S-EPMC6208136 | biostudies-literature
Project description:OBJECTIVES:The purpose of this study was to assess the phenotype of Filamin C (FLNC) truncating variants in dilated cardiomyopathy (DCM) and understand the mechanism leading to an arrhythmogenic phenotype. BACKGROUND:Mutations in FLNC are known to lead to skeletal myopathies, which may have an associated cardiac component. Recently, the clinical spectrum of FLNC mutations has been recognized to include a cardiac-restricted presentation in the absence of skeletal muscle involvement. METHODS:A population of 319 U.S. and European DCM cardiomyopathy families was evaluated using whole-exome and targeted next-generation sequencing. FLNC truncation probands were identified and evaluated by clinical examination, histology, transmission electron microscopy, and immunohistochemistry. RESULTS:A total of 13 individuals in 7 families (2.2%) were found to harbor 6 different FLNC truncation variants (2 stopgain, 1 frameshift, and 3 splicing). Of the 13 FLNC truncation carriers, 11 (85%) had either ventricular arrhythmias or sudden cardiac death, and 5 (38%) presented with evidence of right ventricular dilation. Pathology analysis of 2 explanted hearts from affected FLNC truncation carriers showed interstitial fibrosis in the right ventricle and epicardial fibrofatty infiltration in the left ventricle. Ultrastructural findings included occasional disarray of Z-discs within the sarcomere. Immunohistochemistry showed normal plakoglobin signal at cell-cell junctions, but decreased signals for desmoplakin and synapse-associated protein 97 in the myocardium and buccal mucosa. CONCLUSIONS:We found FLNC truncating variants, present in 2.2% of DCM families, to be associated with a cardiac-restricted arrhythmogenic DCM phenotype characterized by a high risk of life-threatening ventricular arrhythmias and a pathological cellular phenotype partially overlapping with arrhythmogenic right ventricular cardiomyopathy.
| S-EPMC6074050 | biostudies-literature
Project description:This SuperSeries is composed of the SubSeries listed below.
2024-08-16 | GSE241120 | GEO