Genetic analysis in cardiovascular disease: a clinical perspective

Cardiovascular Disease in Childhood, Adolescent, and Young Adult Cancer Survivors: The Impact of Family History of Premature Heart Disease

Purpose: Childhood, adolescent, and young adult (CAYA) cancer survivors (age 0-39 years at diagnosis) are at increased risk of cardiovascular disease (CVD). Family history of early heart disease increases the risk of CVD in the general population; however, it is unknown whether this association is seen in CAYA cancer survivors. Methods: Self-report data from the National Health and Nutrition Examination Survey (2005-2018) were used to identify CAYA survivors (>5 years post-diagnosis). The risk of CVD based on family history status (parent or sibling with a diagnosis of heart attack or angina before age 50 years), personal sociodemographic factors, personal medical history factors, and personal behavioral risk factors was determined using logistic regression models. Results: Included were 95 CAYA survivors with CVD and 491 CAYA survivors without CVD. The odds of CVD were significantly higher in survivors with a first-degree family history of early heart disease (odds ratio [OR]: 2.06, 95% confidence interval [CI]: 1.14-3.74). A history of diabetes (OR: 2.61, 95% CI: 1.41-4.84), hypertension (OR: 1.81, 95% CI: 1.04-3.16), and any smoking (OR: 2.19, 95% CI: 1.19-4.02) was also associated with higher odds of CVD in CAYA survivors. Reporting any physical activity in the past month was associated with lower odds (OR: 0.54, 95% CI: 0.30-0.97) of CVD. Conclusions: Family history of early heart disease was associated with increased odds of CVD in CAYA cancer survivors. Obtaining complete and accurate family history information is important both at time of diagnosis and throughout follow-up.

Coagulation Factor XIII Val34Leu Polymorphism in the Prediction of Premature Cardiovascular Events-The Results of Two Meta-Analyses

Background: Polymorphisms within the gene that encodes for coagulation factor XIII (FXIII) have been suggested to be involved in the pathogeneses of ischemic stroke (IS) and myocardial infarction (MI). The Val34Leu polymorphism is one of the most commonly analysed FXIII polymorphisms. However, studies on the role of the Val34Leu polymorphism in the aetiology of vascular diseases often show contradictory results. In the present meta-analysis, we aimed to pool data from available articles to assess the relationship between the FXIII Val34Leu polymorphism and the susceptibilities to IS of undetermined source and premature MI in patients aged below 55 years. Methods: We searched databases (PubMed, Embase, Google Scholar, SciELO, and Medline) using specific keywords (the last search was in January 2022). Eventually, 18 studies (627 cases and 1639 controls for IS; 2595 cases and 4255 controls for MI) met the inclusion criteria. Data were analysed using RevMan 5.4 and StatsDirect 3 link software. The relation between Val34Leu polymorphism and disease was analysed in five genetic models, i.e., dominant, recessive, additive, heterozygous, and allelic. Results: No relation between Val34Leu polymorphism and IS in young adults was observed in all analysed genetic models. For premature MI, significant pooled OR was found between the carrier state of the Leu allele (Val/Leu + Leu/Leu vs. Val/Val) and a lack of MI, suggesting its protective role (OR = 0.80 95%CI 0.64–0.99, p = 0.04). A similar finding was observed for the heterozygous model in MI (Val/Leu vs. Val/Val) (OR = 0.77 95%CI 0.61–0.98, p = 0.03). No relation was found for the recessive, additive, and allelic models in MI. Conclusions: In the population of young adults, no positive correlation was found between the FXIII Val34Leu polymorphism and IS of undetermined source in any of the analysed genetic models. In turn, the carrier state of the 34Leu allele as well as FXIII heterozygotes themselves were found to play a protective role in relation to premature MI.

The rs46522 Polymorphism of the Ubiquitin-Conjugating Enzyme E2Z Gene Is Associated with Abnormal Metabolic Parameters in Patients with Myocardial Infarction: The Genetics of Atherosclerosis Disease Mexican Study

The participation of ubiquitin-conjugating enzyme E2Z (UBE2Z) in atherosclerosis has been reported. We aimed to evaluate the association of the rs46522 polymorphism of the UBE2Z gene with myocardial infarction (MI) and other clinical and metabolic components in the Mexican population. A total of 2128 individuals (1023 patients with MI and 1105 healthy controls) were included. rs46522 was genotyped using the 5' exonuclease TaqMan genotyping assay. A similar polymorphism distribution was observed between patients and healthy controls. The association between rs46522 polymorphism and cardiometabolic parameters was evaluated separately in the two groups. In the control group, rs46522 polymorphism was associated with increased risk of developing low-density lipoprotein cholesterol ≥130 mg/dL (odds ratio [OR] = 1.249, p_additive = 0.018; OR = 1.479, p_recessive = 0.015; OR = 1.589, p_{codominant 2} = 0.013). On the other hand, in MI patients, it was observed that rs46522 polymorphism was associated with an increased risk of developing high levels of alanine transaminase (OR = 1.297, p_heterozygote = 0.043) and aspartate transaminase (OR = 1.453, p_dominant = 0.009; OR = 1.592, p_heterozygote = 0.001; OR = 1.632, p_{codominant 1} = 0.001). Our results suggest that the UBE2Z gene rs46522 polymorphism is associated with abnormal metabolic parameters in Mexican patients with MI.

Insulin-like growth factors and their potential role in cardiac epigenetics

Cardiovascular disease (CVD) constitutes a major public health threat worldwide, accounting for 17.3 million deaths annually. Heart disease and stroke account for the majority of healthcare costs in the developed world. While much has been accomplished in understanding the pathophysiology, molecular biology and genetics underlying the diagnosis and treatment of CVD, we know less about the role of epigenetics and their molecular determinants. The impact of environmental changes and epigenetics in CVD is now emerging as critically important in understanding the origin of disease and the development of new therapeutic approaches to prevention and treatment. This review focuses on the emerging role of epigenetics mediated by insulin like-growth factors-I and -II in major CVDs such as heart failure, cardiac hypertrophy and diabetes.

Cardiac troponin T (TNNT2) mutations in chinese dilated cardiomyopathy patients

BACKGROUND

Dilated cardiomyopathy (DCM) is one of the leading causes of heart failure with high morbidity and mortality. Although more than 40 genes have been reported to cause DCM, the role of genetic testing in clinical practice is not well defined. Mutations in the troponin T (TNNT2) gene represent an important subset of known disease-causing mutations associated with DCM. Therefore, the aim of the present study was to determine the genetic variations in TNNT2 and the associations of those variations with DCM in Chinese patients.

METHODS

An approximately 4 kb fragment of the TNNT2 gene was isolated from 103 DCM patients and 192 healthy controls and was analyzed by DNA sequence analysis for genetic variations.

RESULTS

A total of 6 TNNT2 mutations were identified in 99 patients, including a G321T missense mutation (Leu84Phe) and 5 novel intronic mutations. Alleles of two novel SNPs (c.192 + 353 C>A, OR = 0.095, 95% CI: 0.013-0.714, P = 0.022; c.192 + 463 G>A, OR = 0.090, 95% CI: 0.012-0.675, P = 0.019) and SNP rs3729843 (OR = 1.889, 95% CI: 1.252-2.852; P = 0.002) were significantly correlated with DCM.

CONCLUSIONS

These results suggest that the missense mutation (Leu84Phe) and two novel SNPs (c.192 + 353 C>A, c.192 + 463 G>A) in TNNT2 gene might be associated with DCM in the Chinese population.

Rapid molecular genetic diagnosis of hypertrophic cardiomyopathy by semiconductor sequencing

Background

Rapidly determining the complex genetic basis of Hypertrophic cardiomyopathy (HCM) is vital to better understanding and optimally managing this common polygenetic cardiovascular disease.

Methods

A rapid custom Ion-amplicon-resequencing assay, covering 30 commonly affected genes of HCM, was developed and validated in 120 unrelated patients with HCM to facilitate genetic diagnosis of this disease. With this HCM-specific panel and only 20 ng of input genomic DNA, physicians can, for the first time, go from blood samples to variants within a single day.

Results

On average, this approach gained 595628 mapped reads per sample, 95.51% reads on target (64.06 kb), 490-fold base coverage depth and 93.24% uniformity of base coverage in CDS regions of the 30 HCM genes. After validation, we detected underlying pathogenic variants in 87% (104 of 120) samples. Tested seven randomly selected HCM genes in eight samples by Sanger sequencing, the sensitivity and false-positive-rate of this HCM panel was 100% and 5%, respectively.

Conclusions

This Ion amplicon HCM resequencing assay provides a currently most rapid, comprehensive, cost-effective and reliable measure for genetic diagnosis of HCM in routinely obtained samples.

Polymorphism of ZBTB17 gene is associated with idiopathic dilated cardiomyopathy: a case control study in a Han Chinese population

BACKGROUND

Dilated cardiomyopathy (DCM) has been extensively investigated for many years, but its pathogenesis remains uncertain. The ACTC1 gene was the first sarcomeric gene whose mutation was shown to cause DCM; recent studies have indicated that the HSPB7 and ZBTB17 genes are also associated with DCM. To assess the potential role of these three genes in DCM, we examined 11 single nucleotide polymorphisms (SNPs) in the ZBTB17, HSPB7 and ACTC1 genes: namely, rs10927875 in ZBTB17; rs1739843, rs7523558, and rs6660685 in HSPB7; rs533021, rs589759, rs1370154, rs2070664, rs3759834, rs525720 and rs670957 in ACTC1.

METHODS

A total of 97 DCM patients and 189 controls were included in the study. All SNPs were genotyped by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS).

RESULTS

The genotype of SNP rs10927875 in ZBTB17 (OR=5.19, 95% CI =1.00 to 27.03, P=0.05) was associated with DCM in a Han Chinese population. There was no difference in genotype or allele frequencies in ACTC1 or HSPB7 between DCM patients and control subjects.

CONCLUSION

The ZBTB17 polymorphism rs10927875 appears to play a role in the susceptibility of the Han Chinese population to DCM.

TNNT2 gene polymorphisms are associated with susceptibility to idiopathic dilated cardiomyopathy in the Han Chinese population

Background. Idiopathic dilated cardiomyopathy (DCM) is characterized by ventricular chamber enlargement and systolic dysfunction. The pathogenesis of DCM remains uncertain, and the TNNT2 gene is potentially associated with DCM. To assess the role of TNNT2 in DCM, we examined 10 tagging single nucleotide polymorphisms (SNPs) in the patients. Methods. A total of 97 DCM patients and 189 control subjects were included in the study, and all SNPs were genotyped by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Results. In the TNNT2 gene, there was a significant association between DCM and genotype for the tagging SNPs rs3729547 (χ² = 6.63, P = 0.036, OR = 0.650, and 95% CI = 0.453–0.934) and rs3729843 (χ² = 9.787, P = 0.008, OR = 1.912, and 95% CI = 1.265–2.890) in the Chinese Han population. Linkage disequilibrium (LD) analysis showed that the SNPs rs7521796, rs2275862, rs3729547, rs10800775, and rs1892028, which are approximately 6 kb apart, were in high LD (D′ > 0.80) in the DCM patients. Conclusion. These results suggest that the TNNT2 polymorphisms might play an important role in susceptibility to DCM in the Chinese Han population.

Genetic predictors for cardiovascular disease in hispanics

A less favorable cardiovascular risk factor profile but paradoxically lower cardiovascular morbidity and mortality have been observed in Hispanics--a pattern often referred to as the Hispanic paradox. It has been proposed that the specific genetic susceptibility of this admixed population and gene-environment interactions may partly explain the paradox. During the past few years, there have been major advances in the identification of genetic risk factors using genome-wide association studies (GWAS) for cardiovascular disease, especially in Caucasians. However, no GWAS of cardiovascular disease have been reported in Hispanics. In the Costa Rican Heart Study, we reported both the consistency and disparity of genetic effects on risk of coronary heart disease (CHD) between Hispanics and other ethnic groups. We demonstrated that the improvement in the identified genetic markers on discrimination of CHD in Hispanics was modest. Future genetic research on Hispanics should consider the diversity in genetic structure, lifestyle, and socioeconomics among various subpopulations and comprehensively evaluate potential gene-environment interactions in relation to cardiovascular risk.

Cardiac-specific inducible and conditional gene targeting in mice

Mouse genetic engineering has revolutionized our understanding of the molecular and genetic basis of heart development and disease. This technology involves conditional tissue-specific and temporal transgenic and gene targeting approaches, as well as introduction of polymorphisms into the mouse genome. These approaches are increasingly used to elucidate the genetic pathways underlying tissue homeostasis, physiology, and pathophysiology of adult heart. They have also led to the development of clinically relevant models of human cardiac diseases. Here, we review the technologies and their limitations in general and the cardiovascular research community in particular.