Genetic variant burden and adverse outcomes in pediatric cardiomyopathy

The Impact of Integration of a Genetic Clinic Into a Pediatric Cardiac Unit

BACKGROUND

Previously published studies suggest that genetic or environmental causes can be observed in 20-30% of congenital heart disease (CHD) patients, which include aneuploidy, single gene defects, pathological copy number variations, and de novo autosomal dominant and recessive inheritance. Moreover, the genetic background of childhood cardiomyopathies (CMs) has not been elucidated well.

OBJECTIVE

The study highlights the value of genetic assessment in diagnosing and family counseling for CHD and pediatric CM patients referred to the genetic clinic in a pediatric cardiology department.

METHODS

The study involved patients less than 18 years of age attending the cardiogenetic clinic in the pediatric cardiology department between December 2010 and February 2019. The following patient categories who had genetic evaluation were included: CHD in the presence of a syndromic phenotype, patients with CHD having extracardiac congenital anomalies or delayed development, hypertrophic and dilated CM patients, patients with dilated aortic root and ascending aorta, significant CHD in siblings or first-degree relatives, suspected channelopathies; and interrupted aortic arch abnormalities.

RESULTS

A total of 285 patients were evaluated in the cardiogenetic clinic. The mean age was 20.2 months, with a range of 0-168. Females and males constituted 153 (53.7%) and 132 (46.3%), respectively. The most common cause of referral to the genetic clinic was the presence of CM (N=134 (46.3%)): hypertrophic CM in 24% and dilated CM in 20% of cases. Seventy-six patients (26.7%) had positive genetic results. The most common genetic abnormality was familial infantile hypertrophic CM-causing gene ELAC2 in 19 (23.5%) cases.

CONCLUSION

It may be beneficial for any pediatric cardiology unit to provide an established genetic clinic. Using a genetic clinic will enhance understanding of CHD pathophysiology, family education, and genetic counseling. Agreement on a well-written protocol and the way forward to specify what congenital heart conditions require genetic investigation should be clarified.

Electrocardiographic Findings in Genotype-Positive and Non-sarcomeric Children with Definite Hypertrophic Cardiomyopathy and Subclinical Variant Carriers

In children with hypertrophic cardiomyopathy (HCM), the genotype-phenotype association of abnormal electrocardiographic (ECG) features in the backdrop of gene positivity has not been well described. This study aimed to describe the abnormal ECG findings in children with HCM harboring who have genetic variants and determine the association with major adverse cardiac events (MACE). We retrospectively analyzed 81 variants-positive, phenotype-positive (V+P+), 66 variant-positive, phenotype-negative (V+P-), and 85 non-sarcomeric subjects. We analyzed ECG findings and clinical outcomes in the three groups of subjects. Repolarization abnormalities (ST and T wave changes) and pathologic Q waves were the most common abnormalities in variant and non-sarcomeric subjects. The V+P+ group showed higher occurrence of ST segment changes and T wave abnormalities compared to V+P- group. Independent predictors of MACE included ST segment changes (OR 3.54, CI 1.20-10.47, p = 0.022). T wave changes alone did not predict outcome (OR 2.13, CI 0.75-6.07, p = 0.157), but combined repolarization abnormalities (ST+T changes) were strong predictors of MACE (OR 5.84, CI 1.43-23.7, p = 0.014) than ST segment changes alone. Maximal wall z score by echocardiography was a predictor of MACE (OR 1.21, CI 1.07-1.37, p = 0.002). Despite the presence of significant myocardial hypertrophy (z score > 4.7), voltage criteria for LVH were much less predictive. In the non-sarcomeric group, RVH was significantly associated with MACE (OR 3.85, CI 1.08-13.73, p = 0.038). These abnormal ECG findings described on the platform of known genetic status and known myocardial hypertrophy may add incremental value to the diagnosis and surveillance of disease progression in children with HCM. Select ECG findings, particularly repolarization abnormalities, may serve as predictors of MACE in children.

Analysis of the disease burden of cardiomyopathy in children aged 0-14 years in China from 1990 to 2019

Objectives

To assess the disease burden and changing trend of cardiomyopathy in children aged 0-14 years in China from 1990 to 2019.

Methods

This study was based on the Global Burden of Disease Study 2019; the age-specific prevalence rate, mortality rate and disability-adjusted life year (DALY) rate were used for analysis. Estimated annual percentage change (EAPC) in burden rate and its 95% confidence interval were calculated. The data of China were compared with the global average level.

Results

In 2019, the numbers of prevalence, deaths, and DALYs of cardiomyopathy in children aged 0-14 years in China were 4,493 [95% uncertainty interval (UI): 2687 ~ 6,838], 434 (95%UI: 337 ~ 565) and 37,522 (95%UI: 29,321 ~ 48,891), with declining amplitudes of 16.32, 70.56, and 70.74%, compared with 1990, respectively. In 2019, the prevalence rate of cardiomyopathy in Chinese children aged 0-14 years was 2.00/100,000 (95%UI: 1.2/100,000 ~ 3.04/100,000), higher than 1990 [1.66/100,000 (95%UI:1.00/100,000 ~ 2.53/100,000)]; mortality rate was 0.19/100,000 (95%UI: 0.15/100,000 ~ 0.25/100,000), significantly lower than 1990 [0.46/100,000 (95%UI: 0.25/100,000 ~ 0.95/100,000)]; DALY rate was 16.69/100,000 (95%UI: 13.04/100,000 ~ 21.75/100,000), also significantly lower than 1990 [39.71/100,000 (95%UI: 22.06/100,000 ~ 82.8/100,000)]. All burden rates of cardiomyopathy in Chinese children aged 0-14 years old were all lower than the global averages of 2019; the burden rates of male children were higher than female children. In all calendar years from 1990 to 2019, the mortality and DALY rates of children younger than 1-year-old were significantly higher than in the other age groups of 0-14 years old. From 1990 to 2019, the prevalence rate of cardiomyopathy aged 0-14 years old gradually increased, with EAPC of 0.82 (95%CI: 0.71-0.93); mortality rate and DALY rate decreased [EAPC = -2.32 (95%CI: -2.59 to -2.05)].

Conclusion

From 1990 to 2019, the disease burden of cardiomyopathy in children of China aged 0-14 years was heterogeneous; the burden of male children was higher than females; and the burden of cardiomyopathy in children younger than 1 year old needs more attention.

Juvenile-onset multifocal atrial arrhythmias, atrial standstill and compound heterozygosity of genetic variants in TAF1A: sentinel event for evolving dilated cardiomyopathy-a case report

Background

Juvenile onset of extensive atrial electromechanical failure, including atrial standstill, is a rare disease entity that may precede ventricular cardiomyopathy. Genetic variants associated with early-onset atrioventricular (AV) cardiomyopathy are increasingly recognized.

Case summary

A 16-year-old patient presented with atrial brady- and tachyarrhythmias and concomitant impaired atrial electromechanical function (atrial standstill). The atrial phenotype preceded the development of a predominantly right-sided AV dilated cardiomyopathy with pronounced myocardial fibrosis. A His-bundle pacemaker was installed for high-degree AV conduction block and sinus arrest. Using familial-based whole-exome sequencing, a missense mutation and a copy number variant deletion (compound heterozygosity) of the TAF1A gene (involved in ribosomal RNA synthesis) were identified.

Discussion

Juvenile onset of severe atrial electromechanical failure with atrial arrhythmias should prompt deep pheno- and genotyping and calls for vigilance for downstream cardiomyopathic deterioration.

Disclosing an In-Frame Deletion of the Titin Gene as the Possible Predisposing Factor of Anthracycline-Induced Cardiomyopathy: A Case Report

Anthracycline-induced cardiomyopathy has been noted as a non-neglectable issue in the field of clinical oncology. Remarkable progress has been achieved in searching for inherited susceptible genetic deficits underlying anthracycline cardiotoxicity in the past several years. In this case report, we present the preliminary results of a genetic study in a young male patient who was treated with standard dose anthracycline-based chemotherapy for his acute myeloid leukemia and attacked by acute congestive heart failure after just two courses of therapy. After a survey of 76 target genes, an in-frame deletion of the titin gene was recognized as the most possible genetic defect responsible for his cardiomyopathy caused by anthracycline. This defect proved to pass down from the patient′s mother and did not exist in seven unrelated chemotherapy-treated cancer patients without chemotherapy-induced cardiomyopathy and four other healthy volunteer DNA donors.

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.