Identification of the Novel Variants in Patients With Chronic Thromboembolic Pulmonary Hypertension

2024 Heart Disease and Stroke Statistics: A Report of US and Global Data From the American Heart Association

BACKGROUND

The American Heart Association (AHA), in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, nutrition, sleep, and obesity) and health factors (cholesterol, blood pressure, glucose control, and metabolic syndrome) that contribute to cardiovascular health. The AHA Heart Disease and Stroke Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, brain health, complications of pregnancy, kidney disease, congenital heart disease, rhythm disorders, sudden cardiac arrest, subclinical atherosclerosis, coronary heart disease, cardiomyopathy, heart failure, valvular disease, venous thromboembolism, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The AHA, through its Epidemiology and Prevention Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States and globally to provide the most current information available in the annual Statistical Update with review of published literature through the year before writing. The 2024 AHA Statistical Update is the product of a full year's worth of effort in 2023 by dedicated volunteer clinicians and scientists, committed government professionals, and AHA staff members. The AHA strives to further understand and help heal health problems inflicted by structural racism, a public health crisis that can significantly damage physical and mental health and perpetuate disparities in access to health care, education, income, housing, and several other factors vital to healthy lives. This year's edition includes additional global data, as well as data on the monitoring and benefits of cardiovascular health in the population, with an enhanced focus on health equity across several key domains.

RESULTS

Each of the chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policymakers, media professionals, clinicians, health care administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

Clonal Hematopoiesis of Indeterminate Potential in Chronic Thromboembolic Pulmonary Hypertension: A Multicenter Study

BACKGROUND

The pathogenesis of chronic thromboembolic pulmonary hypertension (CTEPH) is multifactorial and growing evidence has indicated that hematological disorders are involved. Clonal hematopoiesis of indeterminate potential (CHIP) has recently been associated with an increased risk of both hematological malignancies and cardiovascular diseases. However, the prevalence and clinical relevance of CHIP in patients with CTEPH remains unclear.

METHODS

Using stepwise calling on next-generation sequencing data from 499 patients with CTEPH referred to 3 centers between October 2006 and December 2021, CHIP mutations were identified. We associated CHIP with all-cause mortality in patients with CTEPH. To provide insights into potential mechanisms, the associations between CHIP and inflammatory markers were also determined.

RESULTS

In total, 47 (9.4%) patients with CTEPH carried at least 1 CHIP mutation at a variant allele frequency of ≥2%. The most common mutations were in DNMT3A, TET2, RUNX1, and ASXL1. During follow-up (mean, 55 months), deaths occurred in 22 (46.8%) and 104 (23.0%) patients in the CHIP and non-CHIP groups, respectively (P<0.001, log-rank test). The association of CHIP with mortality remained robust in the fully adjusted model (hazard ratio, 2.190 [95% CI, 1.257-3.816]; P=0.006). Moreover, patients with CHIP mutations showed higher circulating interleukin-1β and interleukin-6 and lower interleukin-4 and IgG galactosylation levels.

CONCLUSIONS

This is the first study to show that CHIP mutations occurred in 9.4% of patients with CTEPH are associated with a severe inflammatory state and confer a poorer prognosis in long-term follow-up.

Heart Disease and Stroke Statistics-2023 Update: A Report From the American Heart Association

BACKGROUND

The American Heart Association, in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, diet, and weight) and health factors (cholesterol, blood pressure, and glucose control) that contribute to cardiovascular health. The Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, congenital heart disease, rhythm disorders, subclinical atherosclerosis, coronary heart disease, heart failure, valvular disease, venous disease, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The American Heart Association, through its Epidemiology and Prevention Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States to provide the most current information available in the annual Statistical Update with review of published literature through the year before writing. The 2023 Statistical Update is the product of a full year's worth of effort in 2022 by dedicated volunteer clinicians and scientists, committed government professionals, and American Heart Association staff members. The American Heart Association strives to further understand and help heal health problems inflicted by structural racism, a public health crisis that can significantly damage physical and mental health and perpetuate disparities in access to health care, education, income, housing, and several other factors vital to healthy lives. This year's edition includes additional COVID-19 (coronavirus disease 2019) publications, as well as data on the monitoring and benefits of cardiovascular health in the population, with an enhanced focus on health equity across several key domains.

RESULTS

Each of the chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policymakers, media professionals, clinicians, health care administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

KLF13 Loss‐of‐Function Mutations Underlying Familial Dilated Cardiomyopathy

Background

Dilated cardiomyopathy (DCM), characterized by progressive left ventricular enlargement and systolic dysfunction, is the most common type of cardiomyopathy and a leading cause of heart failure and cardiac death. Accumulating evidence underscores the critical role of genetic defects in the pathogenesis of DCM, and >250 genes have been implicated in DCM to date. However, DCM is of substantial genetic heterogeneity, and the genetic basis underpinning DCM remains elusive in most cases.

Methods and Results

By genome‐wide scan with microsatellite markers and genetic linkage analysis in a 4‐generation family inflicted with autosomal‐dominant DCM, a new locus for DCM was mapped on chromosome 15q13.1–q13.3, a 4.77‐cM (≈3.43 Mbp) interval between markers D15S1019 and D15S1010, with the largest 2‐point logarithm of odds score of 5.1175 for the marker D15S165 at recombination fraction (θ)=0.00. Whole‐exome sequencing analyses revealed that within the mapping chromosomal region, only the mutation in the KLF13 gene, c.430G>T (p.E144X), cosegregated with DCM in the family. In addition, sequencing analyses of KLF13 in another cohort of 266 unrelated patients with DCM and their available family members unveiled 2 new mutations, c.580G>T (p.E194X) and c.595T>C (p.C199R), which cosegregated with DCM in 2 families, respectively. The 3 mutations were absent from 418 healthy subjects. Functional assays demonstrated that the 3 mutants had no transactivation on the target genes ACTC1 and MYH7 (2 genes causally linked to DCM), alone or together with GATA4 (another gene contributing to DCM), and a diminished ability to bind the promoters of ACTC1 and MYH7 . Add, the E144X‐mutant KLF13 showed a defect in intracellular distribution.

Conclusions

This investigation indicates KLF13 as a new gene predisposing to DCM, which adds novel insight to the molecular pathogenesis underlying DCM, implying potential implications for prenatal prevention and precision treatment of DCM in a subset of patients.

PRRX1 Loss-of-Function Mutations Underlying Familial Atrial Fibrillation

Background

Atrial fibrillation (AF) is the most common form of clinical cardiac dysrhythmia responsible for thromboembolic cerebral stroke, congestive heart failure, and death. Aggregating evidence highlights the strong genetic basis of AF. Nevertheless, AF is of pronounced genetic heterogeneity, and in an overwhelming majority of patients, the genetic determinants underpinning AF remain elusive.

Methods and Results

By genome‐wide screening with polymorphic microsatellite markers and linkage analysis in a 4‐generation Chinese family affected with autosomal‐dominant AF, a novel locus for AF was mapped to chromosome 1q24.2–q25.1, a 3.20‐cM (≈4.19 Mbp) interval between markers D1S2851 and D1S218, with the greatest 2‐point logarithm of odds score of 4.8165 for the marker D1S452 at recombination fraction=0.00. Whole‐exome sequencing and bioinformatics analyses showed that within the mapping region, only the mutation in the paired related homeobox 1 (PRRX1) gene, NM_022716.4:c.319C>T;(p.Gln107*), cosegregated with AF in the family. In addition, sequencing analyses of PRRX1 in another cohort of 225 unrelated patients with AF revealed a new mutation, NM_022716.4:c.437G>T; (p.Arg146Ile), in a patient. The 2 mutations were absent in 908 control subjects. Biological analyses in HeLa cells demonstrated that the 2 mutants had significantly diminished transactivation on the target genes ISL1 and SHOX2 and markedly decreased ability to bind the promoters of ISL1 and SHOX2 (2 genes causally linked to AF), although with normal intracellular distribution.

Conclusions

This study first indicates that PRRX1 loss‐of‐function mutations predispose to AF, which provides novel insight into the molecular pathogenesis underpinning AF, implying potential implications for precisive prophylaxis and management of AF.

Targeted next-generation sequencing reveals novel and known variants of thrombophilia associated genes in Saudi patients with venous thromboembolism

BACKGROUND

Thrombophilia is a substantial source of indisposition and mortality in several countries, including Arab populations. Deep venous thrombosis (DVT) with or without pulmonary embolism (PE) is the prevalent clinical manifestation of thrombophilia. While many genetic risk factors for DVT are known, almost all associated with hemostasis, many genetic factors remain unexplained. Nowadays, Next Generation Sequencing (NGS) offers a potential solution that allows several candidate genes to be analyzed simultaneously at a reasonable expense.

METHODS

We performed variant screening in the thrombophilia associated genes in Factor V Leiden (FVL) mutation-negative patients using Ion Torrent Next-generation sequencing (NGS). Ion AmpliSeq panel for 18 genes was designed. Twenty-nine unrelated patients with idiopathic VTE were recruited for NGS.

RESULTS

We were able to identify 19 variants (1 novel and 18 previously reported) in 10 out of 18 targeted genes. Pathogenic variants were identified in 22 patients demonstrating mutation detection rates of 76%. Previously reported variants in the F5, MTHFR, PROS1, PROC, F8, F9, SERPINA10, SERPIND1, and HRG genes were recognized in 21 patients. More than one variant in the targeted genes was detected in some of the patients with VTE. We identified SERPINA10 recurrent variant p.(R88*) in seven patients representing 32% of VTE cases. Additionally, we report one novel variant c.356G > T, p.(G119V) in the F7 gene, considered to be pathogenic in this study.

CONCLUSIONS

Our studies finding illustrates the ability of targeted next-generation sequencing to uncover uncommon/unknown genetic variants that may predispose to thrombophilia. The finding of the novel variant in the F7 gene extends the spectrum of variants affecting thrombosis. While a comparatively small number of subjects have been included in our cohort, the findings summarize the possible genetic features of thrombophilia.

Drug discovery focused on novel pathogenic proteins for pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a fatal disease in which the wall thickening and narrowing of pulmonary microvessels progress due to complicated interactions among processes such as endothelial dysfunction, the proliferation of pulmonary artery smooth muscle cells (PASMCs) and adventitial fibrocytes, and inflammatory cell infiltration. Early diagnosis of patients with PAH is difficult and lung transplantation is the only last choice to save severely ill patients. However, the number of donors is limited. Many patients with PAH show rapid progression and a high degree of pulmonary arterial remodeling characterized by the abnormal proliferation of PASMCs, which makes treatment difficult even with multidrug therapy comprising pulmonary vasodilators. Thus, it is important to develop novel therapy targeting factors other than vasodilation, such as PASMC proliferation. In the development of PAH, inflammation and oxidative stress are deeply involved in its pathogenesis. Excessive proliferation and apoptosis resistance in PASMCs are key mechanisms underlying PAH. Based on those characteristics, we recently screened novel pathogenic proteins and have performed drug discovery targeting those proteins. To confirm the clinical significance of this, we used patient-derived blood samples to evaluate biomarker potential for diagnosis and prognosis. Moreover, we conducted high throughput screening and found several inhibitors of the pathogenic proteins. In this review, we introduce the recent progress on basic and clinical PAH research, focusing on the screening of pathogenic proteins and drug discovery.

Identification of the Novel Variants in Patients With Chronic Thromboembolic Pulmonary Hypertension

Background Although chronic thromboembolic pulmonary hypertension (CTEPH) and acute pulmonary embolism (APE) share some clinical manifestations, a limited proportion of patients with CTEPH have a history of APE. Moreover, in histopathologic studies, it has been revealed that pulmonary vasculature lesions similar to pulmonary arterial hypertension existed in patients with CTEPH. Thus, it remains unknown whether these 3 disorders also share genetic backgrounds. Methods and Results Whole exome screening was performed with DNA isolated from 51 unrelated patients with CTEPH of Japanese ancestry. The frequency of genetic variants associated with pulmonary arterial hypertension or APE in patients with CTEPH was compared with those in the integrative Japanese Genome Variation Database 3.5KJPN. Whole exome screening analysis showed 17 049 nonsynonymous variants in patients with CTEPH. Although we found 6 nonsynonymous variants that are associated with APE in patients with CTEPH, there was no nonsynonymous variant associated with pulmonary arterial hypertension. Patients with CTEPH with a history of APE had nonsynonymous variants of F5, which encodes factor V. In contrast, patients with CTEPH without a history of APE had a nonsynonymous variant of THBD, which encodes thrombomodulin. Moreover, thrombin-activatable fibrinolysis inhibitor, which is one of the pathogenic proteins in CTEPH, was significantly more activated in those who had the variants of THBD compared with those without it. Conclusions These results provide the first evidence that patients with CTEPH have some variants associated with APE, regardless of the presence or absence of a history of APE. Furthermore, the variants might be different between patients with CTEPH with and without a history of APE.