Narrowing Beta-myosin hot spots in its association with hypertrophic cardiomyopathy

Introduction

MYH7 encodes to β-cardiac myosin heavy chain, a large and pleomorphic protein, conformed by different and well-functionally characterized domains. This gene has an enormous contribution to hypertrophic cardiomyopathy (HCM) but also to other cardiomyopathies such as dilated, non-compaction and restrictive cardiomyopathy (and overlapping phenotypes). There are specific and adapted recommendations for classifying variants in this gene regarding its association with HCM; one of the aspects was the location of variants in the head domain, encompassing 181–937 residues as moderate ACMG criteria (Kelli et al., 2018).

Objectives

The purpose of this analysis was to determine if more specific regions of MYH7are enriched in HCM cases. This analysis could help to better characterise those regions where identifying a novel missense variant could reinforce their pathogenicity.

Methods

We included in the analysis 26,929 consecutives unrelated probands in which MYH7 was sequenced by NGS, referred from different countries and centres. We performed an enrichment analysis comparing the prevalence of rare missense variants (pre-established MAF cut-off 0.004%) in cases with the diagnosis of HCM versus their frequency in non-cardiomyopathy cases (internal controls, OR_int, comprising aortic diseases, channelopathies and dyslipidaemias) and in gnomAD population (external controls, OR_ext). Comparison between groups was performed using the Student's t-test; p value <0.05 was considered to indicate statistical significance. The rationale of this grouping was to avoid skewed analysis, given the high degree of overlapping cardiomyopathies observed in this gene.

Results

HCM was the diagnosis in 10,064 cases. 8,975 probands with a non-cardiomyopathy phenotype were used as internal controls; 7,890 cases with other MYH7-related phenotypes (restrictive, dilated, non-compaction and skeletal myopathies) were not included in the analysis. Rare missense variants in MYH7 were enriched in HCM cases (OR_int = 11.15; OR_ext =12.44) and in the pre-established hot spot head domain (OR_int = 16.43; OR_ext = 24.53). However, the regions with the highest odds ratios in both external and internal comparison were the central converter domain (residues 711–755, OR_int = 44.39; OR_ext = 50.27) and actin-binding region (residues 647–664, OR_int =18.77; OR_ext = 69.32). Conversely, the tail region (both S2 subfragment and light meromyosin region, LMM), had the lowest OR in this analysis.

Conclusions

Previously reported hotspot (head) is significantly enriched in HCM cases, but some specific regions within this domain, such as central converter and acting-binding region, could have a relatively higher contribution. These results reinforce the current approach, but on the other hand, show an asymmetric contribution within the head domain. This fact may have an impact on the reassessment of the variant classification in this gene towards a more precise approach.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Health in Code

Genetic variants as determinants of outcome in lamin A/C-related cardiac disease

Background

Current guidelines for the diagnosis and management of familial dilated cardiomyopathy highlight the variables “male sex” and “non-missense type variants” as risk factors for malignant ventricular arrhythmias.

Objective

Quantitative evaluation of prognostic differences between different LMNA variants associated with cardio-laminopathy.

Method

Analysis of cardiac event-free survival (sudden death, major arrhythmic events, death from heart failure and transplantation) with Kaplan-Meier approach in relation to gender & variant LMNA type. The data come from a specific database containing information on more than 1200 carriers of disease-causing LMNA variants. In the first analysis, the groups of comparison were truncating-type variants (LMNAtv) VS the global of pathogenic missense variants in the gene associated with cardiolaminopathy (LMNAm), segregated by gender. In the second analysis, it was considered missense LMNA affecting different residues (p.Arg190, p.Arg377 and p.Arg541), located in different functional domains, with enough data for comparison and with statistically different clinical behavior from that of global pathogenic variants in the gene. They were compared with the group of LMNAtv variants, as reference. The variants included were p.Arg377Cys/His, p.Arg541Cys/Ser/Gly/Pro/His and p.Arg190Trp/Gln/Pro, all of them pathogenic and associated with cardio-laminopathy.

Results

No significant differences were observed in survival between LMNAtv versus LMNAm variants (log rank=0.56) with slightly worse outcomes in males (log rank 0.03). Median survival time was 56 years for men compared to 60 years for women with LMNAtv, and 55 years compared to 66 years, respectively, among carriers of LMNAm (analysis A). In analysis B, statistically significant differences were observed between the groups considered (Log Rank p<0.001). These differences were also clinically relevant (median survival time in groups p.Arg377, LMNAtv, p.Arg190 and p.Arg541 was 60, 58, 50 and 35 years, respectively). Importantly, more than 70% of the cardiac events observed were related to major ventricular arrhythmic episodes.

Conclusions

This quantitative analysis demonstrates that certain missense variants in LMNA may have a similar and even more adverse clinical course than the set of truncation-type variants. These findings highlight the relevance of the specific variant rather than the variant type in guiding actionable therapies to prevent adverse outcomes. Regarding the differences observed between genders, even though they are statistically significant, their magnitude could be clinically not relevant.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Health in Code

Specific actin (ACTC1) missense variants are associated with different overlapping clinical phenotypes and outcomes

Introduction

Pathogenic variants in ACTC1 have been associated with hypertrophic (HCM), dilated (DCM), and left ventricular non-compaction (LVNC) cardiomyopathies. Phenotypes often overlap and atrial septal defects have also been reported. Prognostic data on carriers of these variants are scarce.

Methods and results

The proprietary database of a cardiovascular genetic laboratory was examined to assess penetrance and survival in the 438 carriers (191 families) of 75 missense variants in ACTC1 associated with disease. Their mean age at diagnosis was 32.4 (±18.7) years; 52% were male. The diagnosis was isolated HCM in 47%, LVNC in 17%, and DCM in 9%. LVNC with either HCM or DCM was present in an additional 8%; 13% had an atrial septal defect. Among carriers with echocardiographic information, left ventricular dilatation and dysfunction were described in 13% and 16%, respectively. Ventricular arrhythmias and conduction defects were reported in 94 and 93 carriers. Percentages have not been calculated for the latter, as we cannot ensure a denominator in whom cardiac conduction defects and arrhythmias were certainly discarded.

Overall, 50% of carriers were diagnosed by age 45, and 10% had experienced a major cardiac event. The p.Leu10Met and p.His90Tyr variants (23% of all carriers) demonstrated lower penetrance and a better prognosis than the p.Glu101Lys variant and the other missense variants.

Conclusions

Missense variants in ACTC1 are associated with a range of phenotypes that often overlap. Overall, penetrance and outcomes are age-dependent with a moderate rate of major cardiac events, which are highly dependent on the specific disease-causing variant

Funding Acknowledgement

Type of funding sources: None. Figure 1. The graph shows the percentage of carriers of pathogenic or likely pathogenic missense variants in the ACTC1 gene diagnosed at different ages. Considering all the missense variants in ACTC (in red), 50% of carriers had been diagnosed by age 45. It is worth highlighting the percentage of diagnosis (>15%) in the first 15 years of life, which is higher than the figure usually observed in sarcomeric hypertrophic cardiomyopathy.Figure 2. The graph shows the survival free of major cardiovascular events (sudden, heart failure, stroke-related death, appropriate ICD therapy and heart transplant) in individuals with missense variants in ACTC1. Carriers and affected relatives without genetic study were included. Events were infrequent in two of the most informative variants (p.Leu10Met and p.His90Tyr), and significantly different compared with carriers of the other missense variants (p=0.036 for p.Leu10Met and p=0.015 for p.His90Tyr).

Novel Filamin C missense mutation associated with severe restrictive cardiomyopathy overlapping with left ventricular non-compaction

Introduction

Filamin C gene (FLNC) missense mutations have been previously reported in association with restrictive cardiomyopathy (RCM). The association of FLNC missense variants with non-compaction cardiomyopathy has been reported only in a single proband, but familiar or functional evidence on its causative effect is limited. Overlapping traits among cardiomyopathies related to the same genetic substrate is an emerging and a challenging scenario nowadays.

Purpose

To report a new pathogenic FLNC missense variant in association with a particular form of restrictive/non-compaction overlapping cardiomyopathy.

Methods

The probands fulfill the diagnostic criteria for RCM based on current guidelines. Genetic testing in the probands was performed by NGS, using a broad gene panel (containing over 240 genes). Clinical and genetic cascade screening were expanded to first-degree relatives when it was possible. All mutation carriers underwent clinical assessment including physical examination, 12-lead ECG, echocardiography, cardiac magnetic resonance (MRI), 24h Holter monitoring, and ergometry. None of them had major systemic illnesses nor clinical symptoms of muscular involvement.

Results

The p.Gly2011Arg variant in the FLNC gene was the only relevant variant in the three probands. This variant is virtually absent in the general population (gnomAD). The variant showed a de novo presentation in the first family and segregated with the phenotype in the four studied relatives from the second family (three affected carriers and one unaffected non-carrier). In the third case no familial information was available. This variant affects an ultraconserved residue and is located in a relevant sub-region of Filamin-C, which is necessary for its interaction with other Z-disc proteins. Detailed clinical information is available on all carriers (n=5, 1 male). The average age at diagnosis is 17 years [1–36]. An abnormal ECG was the earliest clinical manifestation (left ventricular hypertrophy by voltage criteria and extensive repolarization abnormalities). Significant hypertrabeculations, mainly at the anterolateral wall and basal anteroseptal segments, was present in all affected carriers. Interestingly, none of them showed an abnormal late-gadolinium enhancement pattern on MRI. The four carriers who were older than 35 years were found to have severe restrictive pattern on echocardiography (functional parameters and secondary features such as bi-atrial dilation), all four suffered from limiting dyspnea, and two are under pre-transplant workup (A-II-1 and B-III-1). One of them had a cardioembolic event (femoral acute ischemia, A-II-1). One relative has recently died from advanced heart failure (B-II-2).

Conclusion

This is the first description on this overlapping (restrictive/non-compaction cardiomyopathy) and aggressive phenotype associated with a missense FLNC variant. This description widens the clinical spectrum related to FLNC missense mutations.

Pedigrees and clinical characterization

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Health in Code

A Type 1 Diabetes Genetic Risk Score Predicts Progression of Islet Autoimmunity and Development of Type 1 Diabetes in Individuals at Risk

OBJECTIVE

We tested the ability of a type 1 diabetes (T1D) genetic risk score (GRS) to predict progression of islet autoimmunity and T1D in at-risk individuals.

RESEARCH DESIGN AND METHODS

We studied the 1,244 TrialNet Pathway to Prevention study participants (T1D patients' relatives without diabetes and with one or more positive autoantibodies) who were genotyped with Illumina ImmunoChip (median [range] age at initial autoantibody determination 11.1 years [1.2-51.8], 48% male, 80.5% non-Hispanic white, median follow-up 5.4 years). Of 291 participants with a single positive autoantibody at screening, 157 converted to multiple autoantibody positivity and 55 developed diabetes. Of 953 participants with multiple positive autoantibodies at screening, 419 developed diabetes. We calculated the T1D GRS from 30 T1D-associated single nucleotide polymorphisms. We used multivariable Cox regression models, time-dependent receiver operating characteristic curves, and area under the curve (AUC) measures to evaluate prognostic utility of T1D GRS, age, sex, Diabetes Prevention Trial-Type 1 (DPT-1) Risk Score, positive autoantibody number or type, HLA DR3/DR4-DQ8 status, and race/ethnicity. We used recursive partitioning analyses to identify cut points in continuous variables.

RESULTS

Higher T1D GRS significantly increased the rate of progression to T1D adjusting for DPT-1 Risk Score, age, number of positive autoantibodies, sex, and ethnicity (hazard ratio [HR] 1.29 for a 0.05 increase, 95% CI 1.06-1.6; P = 0.011). Progression to T1D was best predicted by a combined model with GRS, number of positive autoantibodies, DPT-1 Risk Score, and age (7-year time-integrated AUC = 0.79, 5-year AUC = 0.73). Higher GRS was significantly associated with increased progression rate from single to multiple positive autoantibodies after adjusting for age, autoantibody type, ethnicity, and sex (HR 2.27 for GRS >0.295, 95% CI 1.47-3.51; P = 0.0002).

CONCLUSIONS

The T1D GRS independently predicts progression to T1D and improves prediction along T1D stages in autoantibody-positive relatives.

Historical epidemiology of hepatitis C virus in select countries-volume 4

Due to the introduction of newer, more efficacious treatment options, there is a pressing need for policy makers and public health officials to develop or adapt national hepatitis C virus (HCV) control strategies to the changing epidemiological landscape. To do so, detailed, country-specific data are needed to characterize the burden of chronic HCV infection. In this study of 17 countries, a literature review of published and unpublished data on HCV prevalence, viraemia, genotype, age and gender distribution, liver transplants and diagnosis and treatment rates was conducted, and inputs were validated by expert consensus in each country. Viraemic prevalence in this study ranged from 0.2% in Hong Kong to 2.4% in Taiwan, while the largest viraemic populations were in Nigeria (2 597 000 cases) and Taiwan (569 000 cases). Diagnosis, treatment and liver transplant rates varied widely across the countries included in this analysis, as did the availability of reliable data. Addressing data gaps will be critical for the development of future strategies to manage and minimize the disease burden of hepatitis C.

The present and future disease burden of hepatitis C virus infections with today's treatment paradigm: Volume 4

Factors influencing the morbidity and mortality associated with viremic hepatitis C virus (HCV) infection change over time and place, making it difficult to compare reported estimates. Models were developed for 17 countries (Bahrain, Bulgaria, Cameroon, Colombia, Croatia, Dominican Republic, Ethiopia, Ghana, Hong Kong, Jordan, Kazakhstan, Malaysia, Morocco, Nigeria, Qatar and Taiwan) to quantify and characterize the viremic population as well as forecast the changes in the infected population and the corresponding disease burden from 2015 to 2030. Model inputs were agreed upon through expert consensus, and a standardized methodology was followed to allow for comparison across countries. The viremic prevalence is expected to remain constant or decline in all but four countries (Ethiopia, Ghana, Jordan and Oman); however, HCV-related morbidity and mortality will increase in all countries except Qatar and Taiwan. In Qatar, the high-treatment rate will contribute to a reduction in total cases and HCV-related morbidity by 2030. In the remaining countries, however, the current treatment paradigm will be insufficient to achieve large reductions in HCV-related morbidity and mortality.

Strategies to manage hepatitis C virus infection disease burden-Volume 4

The hepatitis C virus (HCV) epidemic was forecasted through 2030 for 17 countries in Africa, Asia, Europe, Latin America and the Middle East, and interventions for achieving the Global Health Sector Strategy on viral hepatitis targets-"WHO Targets" (65% reduction in HCV-related deaths, 90% reduction in new infections and 90% of infections diagnosed by 2030) were considered. Scaling up treatment and diagnosis rates over time would be required to achieve these targets in all but one country, even with the introduction of high SVR therapies. The scenarios developed to achieve the WHO Targets in all countries studied assumed the implementation of national policies to prevent new infections and to diagnose current infections through screening.

Comparison of two major emergency department-based free-text chief-complaint coding systems

INTRODUCTION

Emergency departments (EDs) using free-text chief-complaint data for syndromic surveillance face a unique challenge because a complaint might be described and coded in multiple ways.

OBJECTIVE

Two major ED-based free-text chief-complaint coding systems were compared for agreement between free-text interpretation and syndrome coding.

METHODS

Chief-complaint data from 21,736 patients at an urban ED were processed through both the New York City Department of Health and Mental Hygiene (DOHMH) syndrome coding system as modified by the Chicago Department of Public Health and the Real-Time Outbreak Detection System Complaint Coder (CoCo, version 2.1, University of Pittsburgh). To account for differences in each system's specified syndromes, relevant syndromes from the DOHMH system were collapsed into the corresponding CoCo categories so that a descriptive comparison could be made. DOHMH classifications were combined to match existing CoCo categories as follows: 1) vomit+diarrhea = Gastrointestinal; 2) cold+respiratory+asthma = Respiratory; 3) fevflu = Constitutional; 4) rash = Rash; 5) sepsis+other = Other, 6) unknown = Unknown.

RESULTS

Overall agreement between DOHMH and CoCo syndrome coding was optimal (0.614 kappa). However, agreement between individual syndromes varied substantially. Rash and Respiratory had the highest agreement (0.711 and 0.594 kappa, respectively). Other and Constitutional had an intermediate level of agreement (0.453 and 0.419 kappa, respectively), but less than optimal agreement was identified for Gastrointestinal and Unknown (0.270 and 0.002 kappa, respectively).

CONCLUSIONS

Although this analysis revealed optimal overall agreement between the two systems evaluated, substantial differences in classification schemes existed, highlighting the need for a consensus regarding chief-complaint classification.

A comparison of digital nonmydriatic fundus imaging with standard 35-millimeter slides for diabetic retinopathy

PURPOSE

The purpose of this study was to compare nonmydriatic digital images with 35-mm slide images for the detection of diabetic retinal findings.

STUDY DESIGN

Comparative, observational case series.

PARTICIPANTS

Twenty-two patients with diabetes.

METHODS

Diabetic patients underwent digital (nonmydriatic fundus camera attached to a digital back) and standard dilated 35-mm retinal photography of three areas: posterior pole, nasal retina, and temporal retina. The images were reviewed by a single masked grader for the presence or absence of specific retinal findings.

PRIMARY OUTCOME MEASURES

Presence or absence of neovascularization of the disc (NVD), neovascularization elsewhere (NVE), venous beading (VB), nerve fiber layer (NFL) hemorrhage, dot-blot hemorrhage, microaneurysm (MA), clinically significant macular edema, cotton wool spot, intraretinal microvascular anomaly (IRMA), hard exudate (HE), and retinal pigment epithelial (RPE) pigmentary changes.

RESULTS

Forty eyes of 22 patients underwent both imaging procedures. The agreement between image type was highest for IRMA (97.5%) and VB (95%) and lowest for RPE pigmentary changes (65%) and MA (62.5%). Sensitivity ranged from 25% (NVD) to 100% (VB). Specificity ranged from 90% (RPE pigmentary changes) to 100% (NVD, NVE, VB, NFL hemorrhage, HE). Positive predictive value ranged from 50% (IRMA) to 100% (NVD, NVE, HE, NFL, VB). Negative predictive value ranged from 48% (MA) to 100% (IRMA).

CONCLUSIONS

Nonmydriatic digital fundus imaging for detection of diabetic retionopathy has a low sensitivity rate and a high specificity rate and is less clinically useful than standard dilated 35-mm fundus slide images.