Molecular analysis of dilated and left ventricular noncompaction cardiomyopathies in Egyptian children.

BACKGROUND: Paediatric cardiomyopathy is a progressive, often lethal disorder and the most common cause of heart failure in children. Despite its severe outcomes, the genetic aetiology is still poorly characterised. High-throughput sequencing offers a great opportunity for a better understanding of the genetic causes of cardiomyopathy. AIM: The current study aimed to elucidate the genetic background of cardiomyopathy in Egyptian children. METHODS: This hospital-based study involved 68 patients; 58 idiopathic primary dilated cardiomyopathy and 10 left ventricular noncompaction cardiomyopathy. Cardiomyopathy-associated genes were investigated using targeted next-generation sequencing. RESULTS: Consanguinity was positive in 53 and 70% of dilated cardiomyopathy and left ventricular noncompaction cardiomyopathy patients, respectively. Positive family history of cardiomyopathy was present in 28% of dilated cardiomyopathy and 10% of the left ventricular noncompaction cardiomyopathy patients. In 25 patients, 29 rare variants were detected; 2 likely pathogenic variants in TNNI3 and TTN and 27 variants of uncertain significance explaining 2.9% of patients. CONCLUSIONS: The low genetic detection rate suggests that novel genes or variants might underlie paediatric cardiomyopathy in Egypt, especially with the high burden of consanguinity. Being the first national and regional report, our study could be a reference for future genetic testing in Egyptian cardiomyopathy children. Genome-wide tests (whole exome/genome sequencing) might be more suitable than the targeted sequencing to investigate the primary cardiomyopathy patients. Molecular characterisation of cardiomyopathies in different ethnicities will allow for global comparative studies that could result in understanding the pathophysiology and heterogeneity of cardiomyopathies.

Biallelic mutation in MYH7 and MYBPC3 leads to severe cardiomyopathy with left ventricular noncompaction phenotype.

Dominant mutations in the MYH7 and MYBPC3 genes are common causes of inherited cardiomyopathies, which often demonstrate variable phenotypic expression and incomplete penetrance across family members. Biallelic inheritance is rare but allows gaining insights into the genetic mode of action of single variants. Here, we present three cases carrying a loss-of-function (LoF) variant in a compound heterozygous state with a missense variant in either MYH7 or MYBPC3 leading to severe cardiomyopathy with left ventricular noncompaction. Most likely, MYH7 haploinsufficiency due to one LoF allele results in a clinical phenotype only in compound heterozygous form with a missense variant. In contrast, haploinsufficiency in MYBPC3 results in a severe early-onset ventricular noncompaction phenotype requiring heart transplantation when combined with a de novo missense variant on the second allele. In addition, the missense variant may lead to an unstable protein, as overall only 20% of the MYBPC3 protein remain detectable in affected cardiac tissue compared to control tissue. In conclusion, in patients with early disease onset and atypical clinical course, biallelic inheritance or more complex variants including copy number variations and de novo mutations should be considered. In addition, the pathogenic consequence of variants may differ in heterozygous versus compound heterozygous state.

Noncompaction cardiomyopathy is caused by a novel in-frame desmin (DES) deletion mutation within the 1A coiled-coil rod segment leading to a severe filament assembly defect.

Mutations in DES, encoding desmin protein, are associated with different kinds of skeletal and/or cardiac myopathies. However, it is unknown, whether DES mutations are associated with left ventricular hypertrabeculation (LVHT). Here, we performed a clinical examination and subsequent genetic analysis in a family, with two individuals presenting LVHT with conduction disease and skeletal myopathy. The genetic analysis revealed a novel small in-frame deletion within the DES gene, p.Q113_L115del, affecting the α-helical rod domain. Immunohistochemistry analysis of explanted myocardial tissue from the index patient revealed an abnormal cytoplasmic accumulation of desmin and a degraded sarcomeric structure. Cell transfection experiments with wild-type and mutant desmin verified the cytoplasmic aggregation and accumulation of mutant desmin. Cotransfection experiments were performed to model the heterozygous state of the patients and revealed a dominant negative effect of the mutant desmin on filament assembly. DES:p.Q113_L115del is classified as a pathogenic mutation associated with dilated cardiomyopathy with prominent LVHT.

Cardiomyopathy-Associated Gene 1-Sensitive PKC-Dependent Connexin 43 Expression and Phosphorylation in Left Ventricular Noncompaction Cardiomyopathy.

BACKGROUND/AIMS: Cardiomyopathy-associated gene 1 (CMYA1) plays an important role in embryonic cardiac development, postnatal cardiac remodeling and myocardial injury repair. Abnormal CMYA1 expression may be involved in cardiac dysplasia and primary cardiomyopathy. Our study aims to establish the relationship between CMYA1 and Left ventricular noncompaction cardiomyopathy (LVNC) pathogenesis. METHODS: We explored the effects of CMYA1 on connexins (Cx), which contribute to gap junction intercellular communication (GJIC), and the underlying signaling pathway in human normal tissues, LVNC myocardial tissues and HL1 cells by means of western blotting, RT-qPCR, immunohistochemistry, immunofluorescence, co-immunoprecipitation and scrape loading-dye transfer. RESULTS: CMYA1 expression was inversely associated with Cx43 and Cx40 expression, as determined by gap junction PCR array analysis. An increased expression and disordered distribution of CMYA1 at the intercalated discs in LVNC myocardial tissue was also observed. CMYA1 and Cx43 are co-expressed and interact in myocardial cells. CMYA1 expression was positively correlated with p-Cx43 (S368) via the Protein kinase C (PKC) signaling pathway in myocardial tissue and HL1 cells. The diffusion distance of Lucifer Yellow in the HL1 cells in which CMYA1 was over-expressed or knocked down was significantly less or more than that of the control group, respectively. CONCLUSION: Abnormal CMYA1 expression affects the expression and phosphorylation of Cx43 through the PKC signaling pathway, which is involved in the regulation of GJIC. CMYA1 participates in the molecular mechanism of LVNC pathogenesis.

Left ventricular noncompaction cardiomyopathy in a patient with trisomy 13: A report and review of the literature.

Left ventricular noncompaction cardiomyopathy (LVNC) is characterized by prominent trabecular meshwork, and it is thought to result from arrest of the normal compaction process during embryogenesis. Patients with LVNC may be asymptomatic or have symptoms ranging from heart failure to stroke, life-threatening arrhythmias, or sudden death. The frequency of LVNC in children has increased with longer clinical courses. About 80% of patients with trisomy 13 have a congenital cardiac abnormality, but a clinical description of LVNC with trisomy 13 is lacking because of its poor prognosis and lack of awareness about LVNC. We described a patient with trisomy 13 who was diagnosed with LVNC-dilated phenotype and died suddenly, as well as two additional patients with LVNC. All three patients had chronic heart failure without congenital heart disease and were treated with diuretics. To manage trisomy 13 with or without congenital heart disease, cardiac disease such as LVNC may present at any ages, and therefore cardiac evaluation should be considered as a part of their appropriate management.

Ventricular arrhythmias due to left ventricular noncompaction cardiomyopathy: a diagnosis in hindsight.

Left ventricular noncompaction cardiomyopathy is a rare congenital cardiomyopathy which predisposes to sudden cardiac death. We describe the case of a 24 year-old man who had previously received an implantable cardioverter-defibrillator for sustained ventricular tachycardia and was later diagnosed with left ventricular noncompaction cardiomyopathy during a hospitalisation for device infection.

Genetic landscape in Russian patients with familial left ventricular noncompaction.

Background: Left ventricular noncompaction (LVNC) cardiomyopathy is a disorder that can be complicated by heart failure, arrhythmias, thromboembolism, and sudden cardiac death. The aim of this study is to clarify the genetic landscape of LVNC in a large cohort of well-phenotyped Russian patients with LVNC, including 48 families (n=214). Methods: All index patients underwent clinical examination and genetic analysis, as well as family members who agreed to participate in the clinical study and/or in the genetic testing. The genetic testing included next generation sequencing and genetic classification according to ACMG guidelines. Results: A total of 55 alleles of 54 pathogenic and likely pathogenic variants in 24 genes were identified, with the largest number in the MYH7 and TTN genes. A significant proportion of variants -8 of 54 (14.8%) -have not been described earlier in other populations and may be specific to LVNC patients in Russia. In LVNC patients, the presence of each subsequent variant is associated with increased odds of having more severe LVNC subtypes than isolated LVNC with preserved ejection fraction. The corresponding odds ratio is 2.77 (1.37 -7.37; p <0.001) per variant after adjustment for sex, age, and family. Conclusion: Overall, the genetic analysis of LVNC patients, accompanied by cardiomyopathy-related family history analysis, resulted in a high diagnostic yield of 89.6%. These results suggest that genetic screening should be applied to the diagnosis and prognosis of LVNC patients.

Left Ventricular Noncompaction in Concomitance With Heroin Use Disorder.

Left ventricular noncompaction (LVNC) is a rare congenital condition defined by the presence of prominent trabeculations in the myocardial layer of the left ventricle. The clinical presentation is varied as some patients are asymptomatic and others have symptoms of decompensated heart failure, arrhythmias, or thromboembolism. We present the case of a 42-year-old female with a past medical history of asthma and substance use disorder who presented to the Emergency Department following a syncopal event. The patient had used heroin intranasally, following which she became unresponsive for several minutes. Her husband witnessed the event and initiated chest compressions. When examined by emergency medical services (EMS), she had a palpable pulse and was given naloxone. The patient underwent further evaluation and was admitted for the treatment of aspiration pneumonia. Throughout her hospital stay, she complained of chest pain with musculoskeletal characteristics, likely secondary to chest compressions. However, due to the persistence of pain, she had further cardiac evaluation done. Her electrocardiography (EKG) revealed a normal sinus rhythm with no acute ischemic changes. Her echocardiography revealed left ventricular apical trabeculations with normal systolic and diastolic function, in line with the diagnosis of LVNC. Upon discharge, she was extensively counseled to abstain from substance use and to follow up with cardiology for a cardiac event monitor. Given her initial syncopal event and high-risk substance use behavior, she would benefit from close follow-up for the presence of arrhythmias.

Ventricular Noncompaction With Left Ventricular Thrombus: A Case Report.

Noncompaction cardiomyopathy (NCC) is congenital cardiomyopathy characterized by trabeculations of the left ventricle found on echocardiogram and/or cardiac magnetic resonance imaging (CMRI). This rare disease is associated with thromboembolism and an increased risk of ventricular thrombus formation. We present the case of a 73-year-old female who was admitted for a suspected cerebrovascular accident (CVA), later found on echocardiogram and CMRI to have NCC with left ventricular thrombus. She was started on warfarin indefinitely. We highlight the rarity of this phenomenon as well as the unique questions regarding initiation, length, and choice of therapeutic anticoagulation in the absence of atrial fibrillation in these patients. Consideration of this diagnosis should be made in the absence of other cardioembolic etiologies with prompt management based on available guidelines.

Overlap phenotypes of the left ventricular noncompaction and hypertrophic cardiomyopathy with complex arrhythmias and heart failure induced by the novel truncated DSC2 mutation.

BACKGROUND: The left ventricular noncompaction cardiomyopathy (LVNC) is a rare subtype of cardiomyopathy associated with a high risk of heart failure (HF), thromboembolism, arrhythmia, and sudden cardiac death. METHODS: The proband with overlap phenotypes of LVNC and hypertrophic cardiomyopathy (HCM) complicates atrial fibrillation (AF), ventricular tachycardia (VT), and HF due to the diffuse myocardial lesion, which were diagnosed by electrocardiogram, echocardiogram and cardiac magnetic resonance imaging. Peripheral blood was collected from the proband and his relatives. DNA was extracted from the peripheral blood of proband for high-throughput target capture sequencing. The Sanger sequence verified the variants. The protein was extracted from the skin of the proband and healthy volunteer. The expression difference of desmocollin2 was detected by Western blot. RESULTS: The novel heterozygous truncated mutation (p.K47Rfs*2) of the DSC2 gene encoding an important component of desmosomes was detected by targeted capture sequencing. The western blots showed that the expressing level of functional desmocollin2 protein (~ 94kd) was lower in the proband than that in the healthy volunteer, indicating that DSC2 p.K47Rfs*2 obviously reduced the functional desmocollin2 protein expression in the proband. CONCLUSION: The heterozygous DSC2 p.K47Rfs*2 remarkably and abnormally reduced the functional desmocollin2 expression, which may potentially induce the overlap phenotypes of LVNC and HCM, complicating AF, VT, and HF.

Multiple genetic variants in adolescent patients with left ventricular noncompaction cardiomyopathy.

BACKGROUND: Left ventricular noncompaction cardiomyopathy (LVNC) is a primary cardiomyopathy with an unclear aetiology. The clinical symptoms range from asymptomatic to heart failure, arrhythmias and sudden cardiac death. This study aimed to characterize the genetic features and clinical outcomes of LVNC who underwent heart transplantation (HTx) to reveal the potential genetic pathogenesis. METHODS AND RESULTS: We recruited 16 cases who underwent HTx in our hospital. Exome-sequencing was performed to reveal genetic background. Clinical information and histopathology features of patients were investigated. Gene expression profiling of tissue fibrosis were evaluated by quantitative PCR. The median age of patients was 21 years. Of the 16 patients, 14 harboured multiple gene variants involved in LVNC. Ten of the patients harboured biallelic variants and/or truncating variants. Young patients (<18) with biallelic variants and/or truncating variants and lower LVEF (<45%) at initial symptom deteriorated quickly. Except for noncompaction myocardium, myocardial fibrosis was a remarkable pathological feature, and gene profiles related to immune inflammation and extracellular matrix remodelling were upregulated. CONCLUSIONS: This study showed that multiple pathologic variants were underlie genetic mechanism of LVNC who in high risks, suggesting that genetic screening should be applied to the diagnosis of LVNC. LVNC patient with multiple variants should be considered carefully follow-up. Genetics involved in the phenotype and cardiac fibrosis, and is the major causing for LVNC.

Clinical implications of sarcomere and nonsarcomere gene variants in patients with left ventricular noncompaction cardiomyopathy.

BACKGROUND: Robust data regarding genotype-phenotype correlations in left ventricular noncompaction cardiomyopathy (LVNC) are lacking. METHODS: About 72 cardiomyopathy-related genes were comprehensively screened in a cohort of LVNC patients using targeted sequencing. Baseline and follow-up data were collected. The primary endpoint was a composite of death and heart transplantation. RESULTS: A total of 83 unrelated adult patients were included in analyses. Following stringent classification according to the American College of Medical Genetics and Genomics (ACMG) guidelines, 36 pathogenic variants of 14 genes were detected in 32 patients. Among them, 12 patients carried at least one nonsarcomere variant (NSV). At baseline, NSV carriers had a higher frequency of atrial fibrillation, but lower left ventricular ejection fraction, than did noncarriers. During a median follow-up of 4.2 years, NSV carriers experienced a higher rate of the primary endpoint compared with noncarriers. There was no significant difference in the rate between carriers of sarcomere variant (SV) and noncarriers, as well as between carriers of SV and NSV. The presence of NSV was associated with an increased risk of the primary endpoint independent of age, sex, and cardiac function (hazard ratio: 3.61, 95% confidence interval: 1.42-9.19, p = .002). CONCLUSION: NSV may act as a genetic modifier and worsen the clinical phenotype in patients with LVNC.

Sudden cardiac arrest as the initial presentation for left ventricular noncompaction cardiomyopathy.

A 37-year-old man without a significant medical history had an out-of-hospital sudden cardiac arrest. A bystander started cardiopulmonary resuscitation, and emergency medical services arrived promptly, confirmed ventricular fibrillation, and restored sinus rhythm. An emergent coronary arteriogram was normal. Transthoracic echocardiography revealed a severely reduced left ventricular ejection fraction and suggested left ventricular noncompaction. The patient's heart failure with reduced ejection fraction was treated with carvedilol, lisinopril, and spironolactone, and after he was weaned from the ventilator he received an implantable cardioverter-defibrillator. The patient's identical twin was treated in the same fashion for a sudden cardiac arrest. Although many experts think that left ventricular noncompaction cardiomyopathy is a distinct nosological entity, others think that it is simply a dilated cardiomyopathy with unusually prominent left ventricular trabeculae.

Dilated cardiomyopathy in a pediatric population: etiology and outcome predictors - a single-center experience.

AIM: The aim of the study was to assess predictors of outcome in patients hospitalized for dilated cardiomyopathy (DCM) and severe left ventricular dysfunction. Patients & methods: 83 pediatric patients hospitalized for heart failure due to DCM with coexistent left ventricular dysfunction were enrolled. RESULTS: Overall, 5-year survival free from heart transplantation was 69.8%. Normalization of left ventricular function was achieved in 39.8% of patients during follow-up: younger age, less necessity of inotropic support and other than idiopathic DCM predicted left ventricular function, while familial history for cardiac disease or sudden death and inotropic support during hospitalization were associated with poorer outcome. CONCLUSION: Almost 40% of patients with DCM experienced a complete normalization of cardiac function. Outcome was extremely variable according to the type of DCM.

Ischemic Stroke in a Young Patient Heralding a Left Ventricular Noncompaction Cardiomyopathy.

Strokes in young patients may be the clinical expression of many complex and extremely rare diseases. Uncommon causes constitute less than 5% of all strokes, but are present in 30% of strokes in young patients. We report the case of a young woman whose ischemic stroke led to the diagnosis of a rare embolic cardiomyopathy, left ventricular noncompaction cardiomyopathy, requiring a heart transplant.

Histiocytoid cardiomyopathy and microphthalmia with linear skin defects syndrome: phenotypes linked by truncating variants in NDUFB11.

Variants in NDUFB11, which encodes a structural component of complex I of the mitochondrial respiratory chain (MRC), were recently independently reported to cause histiocytoid cardiomyopathy (histiocytoid CM) and microphthalmia with linear skin defects syndrome (MLS syndrome). Here we report an additional case of histiocytoid CM, which carries a de novo nonsense variant in NDUFB11 (ENST00000276062.8: c.262C > T; p.[Arg88*]) identified using whole-exome sequencing (WES) of a family trio. An identical variant has been previously reported in association with MLS syndrome. The case we describe here lacked the diagnostic features of MLS syndrome, but a detailed clinical comparison of the two cases revealed significant phenotypic overlap. Heterozygous variants in HCCS (which encodes an important mitochondrially targeted protein) and COX7B, which, like NDUFB11, encodes a protein of the MRC, have also previously been identified in MLS syndrome including a case with features of both MLS syndrome and histiocytoid CM. However, a systematic review of WES data from previously published histiocytoid CM cases, alongside four additional cases presented here for the first time, did not identify any variants in these genes. We conclude that NDUFB11 variants play a role in the pathogenesis of both histiocytoid CM and MLS and that these disorders are allelic (genetically related).

Incremental value of contrast echocardiography in the diagnosis of left ventricular noncompaction.

Contrast echocardiography with left ventricular opacification (LVO) improves the definition of endocardium in two-dimensional echocardiography (2DE). This study was aimed to determine whether LVO offered added diagnostic value in noncompaction of left ventricular myocardium (NCVM). A total of 85 patients (40 ± 20 years, 54 males) with suspected NCVM were subjected to transthoracic 2DE and LVO, and 40 healthy volunteers were examined with 2DE and assigned as control subjects. The location of NCVM, the thickness ratio of noncompacted to compacted myocardium (NCR), and the cavity size and ejection fraction of LV were quantified. Results revealed that NCVM was mainly located in the LV medium (53.2%), apical (46.2%) segments, and lateral wall (39.8%). The NCR obtained through LVO was greater than that detected through 2DE (4.2 ± 1.3 vs. 3.3 ±1.2, P < 0.001), and higher inter-correlations and less intra- and inter-observer variabilities were determined in the former than in the latter. The NCVM detection rates were also increased from 63.5% via 2DE to 83.5% via LVO and 89.4% via 2DE combined with LVO (2DE + LVO) (P = 0.0004). The LV cavity size was greater and the LVejection fraction (LVEF) was lower in the NCVM patients than in the control group (P < 0.01). In the NCVM group, the LV cavity size was higher and the LVEF was lower in LVO than in 2DE (P < 0.01). In conclusion, contrast echocardiography contributes significant sensitivity and reproducibility to routine transthoracic echocardiography in NCVM diagnosis. Therefore, this technique should be clinically performed to diagnose suspected NCVM.

Left ventricular noncompaction cardiomyopathy in end-stage heart failure patients undergoing orthotopic heart transplantation.

BACKGROUND: Previous studies reported that left ventricular noncompaction (LVNC) is a cardiomyopathy, familial or sporadic, arising from arrest of the normal process of trabecular remodeling during embryonic development. The diagnosis is usually made by echocardiography, but to date, there has been little research on the occurrence and clinicopathological features of LVNC in the explanted hearts of orthotopic heart transplant (OHT) recipients. DESIGN: The clinical, echocardiographic, and pathologic findings were reviewed for evidence of LVNC, diagnosed by echocardiographic criteria, in 105 patients with end-stage heart failure (HF) undergoing OHT. Analyses of multiple sections of the explanted hearts were carried out. The hearts were evaluated for grades (0, negative; 1, mild/occasional foci; 2, moderate/multiple foci; 3, severe/extensive, diffuse) of fibrosis, reactive and replacement, hypertrophy, myocytolysis in left ventricle, right ventricle, interventricular septum, and atria. Absolute measurements of noncompacted and compacted portions of the left ventricle wall and noncompacted/compacted ratios were calculated. RESULTS: Isolated LVNC was observed in 0 of 54 ischemic cardiomyopathy and in 4 of 51 (7.8%) nonischemic cardiomyopathy patients - 2 men and 2 women, with a mean age±SEM of 34.2±6.9years. The echocardiogram disclosed marked left ventricular dilatation, prominent trabeculations, and left ventricle ejection fraction <20%. Mural thrombi were seen in 3 of 4 (75%) patients. The heart weight mean±SEM was 468±55.3 g (range, 340-600g); noncompacted myocardium was 22±5.8mm, compacted myocardium was 13.2±3.5mm, and noncompacted/compacted ratio was 1.7/1±0.2. The total scores of hypetrophy, myocytolysis, and fibrosis were as follows: left ventricle, 7.7±0.2; right ventricle, 6.2±0.5; interventricular septum, 6.7±0.2; and atria, 7.5±0.3. CONCLUSIONS: LVNC is an unusual form of nonischemic cardiomyopathy in patients suffering from end-stage HF undergoing OHT. The variability in the noncompacted/compacted ratio and discordance between the echocardiographic and pathological findings points to the need for further clarification of diagnostic imaging and diagnostic criteria for LVNC. Further studies in larger series, correlating the anatomoclinical and genetic variables, also would improve our understanding of LVNC as a cause of advanced HF leading to OHT.

Left ventricular noncompaction cardiomyopathy: a case report and literature review.

Left ventricular noncompaction cardiomyopathy (LVNC) is a relatively rare congenital disorder prominently characterized by prominent trabeculations and intertrabecular recesses that communicate with the ventricular cavity rather than the coronary circulation. LVNC can occur in isolation or coexist with other cardiac and/or systemic anomalies, in especial neuromuscular disorders. The clinical presentation varies ranging from asymptomatic patients to patients who develop ventricular arrhythmias, thromboembolism, heart failure and sudden cardiac death. Although LVNC is commonly diagnosed by echocardiography, there are also other useful diagnostic techniques, including contrast ventriculography, CT and MRI. Now, it is being diagnosed more frequently in patients of all ages because of increased awareness and improvements in imaging methods. We described the case of a woman who presented with heart failure for the first time at 62 years of age. The diagnosis was LVNC. Transthoracic echocardiography showed a trabeculated, sponge-like appearance of the ventricular apical and inferolateral segments. After medical management, the patient was asymptomatic at the 1-month follow-up examination. Now we discussed the diagnosis of this case and reviewed the medical literature that pertained to LVNC.