Bioinformatics analysis of sex differences in arrhythmogenic right ventricular cardiomyopathy

Lagging behind the Western countries: the knowledge gaps of gender differences in heart failure in Asia

Gender differences in heart failure (HF), ranging from epidemiological and pathophysiological factors to therapeutic response and prognosis, have been well documented in Western countries, especially in Europe and North America. The above gender differences in HF found in Westerners are rarely investigated in Asians. In this review, we explore the worrying knowledge gap on the gender differences in HF that existed in Asia in contrast with Western populations based on the following four aspects: epidemiology, risk factors, therapy, and prognosis. Finally, we conclude that investigations of gender differences in HF in Asia lag behind those in Europe and North America. Future work is required to establish and better use the high-level, population-based cohorts and develop our own high-quality, convincing clinical trials to deliver robust gender-specific conclusions in Asia.

Heart Failure in Women

Heart failure (HF) in women is one of the leading causes in women after coronary artery diseases. There are gender differences at every aspect of HF. These females usually present in older age with significant comorbidities. Even though there are few risk factors common to males and females for the development of HF, diabetes and hypertension are considered more stronger association for the development of HF in females than in males. There are certain sex-specific factors such as abnormal pregnancies and breast cancer therapies in addition to genetic predisposition for the development of cardiomyopathies, especially postpartum cardiomyopathy in female. Usually, females have HF with preserved ejection fraction when compared to men who more frequently have HF due to reduced ejection fraction. Even in the left ventricular remodeling to injury is different in both sexes. The main aim of this review is to bring the sex differences in HF and to stress the need of separate guidelines for females with HF for better outcome.

Genetic Diagnostic Yield and Novel Causal Genes of Congenital Heart Disease

Congenital heart disease (CHD) is the most common congenital malformation in fetuses and neonates, which also represents a leading cause of mortality. Although significant progress has been made by emerging advanced technologies in genetic etiology diagnosis, the causative genetic mechanisms behind CHD remain poorly understood and more than half of CHD patients lack a genetic diagnosis. Unlike carefully designed large case-control cohorts by multicenter trials, we designed a reliable strategy to analyze case-only cohorts to utilize clinical samples sufficiently. Combined low-coverage whole-genome sequencing (WGS) and whole-exome sequencing (WES) were simultaneously conducted in a patient-only cohort for identifying genetic etiologies and exploring candidate, or potential causative CHD-related genes. A total of 121 sporadic CHD patients were recruited and 34.71% (95% CI, 26.80 to 43.56) was diagnosed with genetic etiologies by low-coverage WGS and WES. Chromosomal abnormalities and damaging variants of CHD-related genes could explain 24.79% (95% CI, 17.92 to 33.22) and 18.18% (95% CI, 12.26 to 26.06) of CHD patients, separately, and 8.26% (95% CI, 4.39 to 14.70) of them have simultaneously detected two types of variants. Deletion of chromosome 22q11.2 and pathogenic variants of the COL3A1 gene were the most common recurrent variants of chromosomal abnormalities and gene variants, respectively. By in-depth manual interpretation, we identified eight candidate CHD-causing genes. Based on rare disease-causing variants prediction and interaction analysis with definitive CHD association genes, we proposed 86 genes as potential CHD-related genes. Gene Ontology (GO) enrichment analysis of the 86 genes revealed regulation-related processes were significantly enriched and processes response to regulation of muscle adaptation might be one of the underlying molecular mechanisms of CHD. Our findings and results provide new insights into research strategies and underlying mechanisms of CHD.

Sex differences in disease progression and arrhythmic risk in patients with arrhythmogenic cardiomyopathy

AIMS

We aimed to assess sex-specific phenotypes and disease progression, and their relation to exercise, in arrhythmogenic cardiomyopathy (AC) patients.

METHODS AND RESULTS

In this longitudinal cohort study, we included consecutive patients with AC from a referral centre. We performed echocardiography at baseline and repeatedly during follow-up. Patients' exercise dose at inclusion was expressed as metabolic equivalents of task (MET)-h/week. Ventricular arrhythmia (VA) was defined as aborted cardiac arrest, sustained ventricular tachycardia, or appropriate therapy by implantable cardioverter-defibrillator. We included 190 AC patients (45% female, 51% probands, age 41 ± 17 years). Ventricular arrhythmia had occurred at inclusion or occurred during follow-up in 85 patients (33% of females vs. 55% of males, P = 0.002). Exercise doses were higher in males compared with females [25 (interquartile range, IQR 14-51) vs. 12 (IQR 7-22) MET-h/week, P < 0.001]. Male sex was a marker of proband status [odds ratio (OR) 2.6, 95% confidence interval (CI) 1.4-5.0, P = 0.003] and a marker of VA (OR 2.6, 95% CI 1.4-5.0, P = 0.003), but not when adjusted for exercise dose and age (adjusted OR 1.8, 95% CI 0.9-3.6, P = 0.12 and 1.5, 95% CI 0.7-3.1, P = 0.30, by 5 MET-h/week increments). In all, 167 (88%) patients had ≥2 echocardiographic examinations during 6.9 (IQR 4.7-9.8) years of follow-up. We observed no sex differences in deterioration of right or left ventricular dimensions and functions.

CONCLUSION

Male AC patients were more often probands and had higher prevalence of VA than female patients, but not when adjusting for exercise dose. Importantly, disease progression was similar between male and female patients.

Cardiomyopathies in China: A 2018-2019 state-of-the-art review

Cardiomyopathies are diseases of the cardiac muscle and are often characterized by ventricular dilation, hypertrophy, and cardiac arrhythmia. Patients with cardiomyopathies often experience sudden death and cardiac failure and require cardiac transplantation during the course of disease progression. Early diagnosis, differential diagnosis, and genetic consultation depend on imaging techniques, genetic testing, and new emerging diagnostic tools such as serum biomarkers. The molecular genetics of cardiomyopathies has been widely studied recently. The discovery of mechanisms underlying heterogeneity and overlapping of the phenotypes of cardiomyopathies has revealed the existence of disease modifiers, and this has led to the emergence of novel disease-modifying therapy. This 2018-2019 state-of-the-art review outlines the pathogenesis, diagnosis, and treatment of cardiomyopathies in China.