Cascade Screening Of Relatives Research Articles

Cardiomyopathies: a practical approach to the assessment and management of patients and their families

The new 2023 European Society of Cardiology (ESC) Guidelines for the management of cardiomyopathies addresses all cardiomyopathies in a single document for the first time. The focus is on a phenotype-oriented diagnostic approach, multimodal imaging and genetic testing to establish the most accurate diagnosis possible. Additionally, new recommendations for risk stratification for sudden cardiac death in various cardiomyopathy phenotypes are provided. MRI and genetic testing have significantly gained importance in this context. Recommendations for comprehensive clinical and genetic cascade screening in relatives of individuals with cardiomyopathies have been revised. This article presents the most important innovations of these guidelines in a practice-oriented approach.

Intention to Inform Relatives, Rates of Cascade Testing, and Preference for Patient-Mediated Communication in Families Concerned with Hereditary Breast and Ovarian Cancer and Lynch Syndrome: The Swiss CASCADE Cohort.

Simple SummaryThis paper presents important information for the implementation of cascade screening programs for hereditary breast and ovarian cancer (HBOC) and Lynch syndrome (LS). The study examined theory-based predictors of index cases’ intention to invite relatives to a family-based cohort, rates of cascade testing among relatives, and preferences of those who carry a pathogenic variant for patient- or provider-mediated communication of testing results to untested relatives. While index cases are equally likely to invite relatives of both genders, males are more likely to not respond to the invitation, especially for HBOC. Findings have implications for tailoring cascade screening programs.Cascade screening for Tier 1 cancer genetic conditions is a significant public health intervention because it identifies untested relatives of individuals known to carry pathogenic variants associated with hereditary breast and ovarian cancer (HBOC) and Lynch syndrome (LS). The Swiss CASCADE is a family-based, open-ended cohort, including carriers of HBOC- and LS-associated pathogenic variants and their relatives. This paper describes rates of cascade screening in relatives from HBOC- and LS- harboring families, examines carriers’ preferences for communication of testing results, and describes theory-based predictors of intention to invite relatives to a cascade screening program. Information has been provided by 304 index cases and 115 relatives recruited from September 2017 to December 2021. On average, 10 relatives per index case were potentially eligible for cascade screening. Approximately 65% of respondents wanted to invite relatives to the cohort, and approximately 50% indicated a preference for patient-mediated communication of testing results, possibly with the assistance of digital technology. Intention to invite relatives was higher for first- compared to second- and third-degree relatives, but was not different between syndromes or based on relatives’ gender. The family environment and carrying pathogenic variants predicts intention to invite relatives. Information helps optimize delivery of tailored genetic services.

Polygenic contribution for familial hypercholesterolemia (FH).

The present review summarizes different polygenic risk scores associated with hypercholesterolemia applied to cohorts with a genetic diagnosis of familial hypercholesterolemia (FH). Several single-nucleotide polymorphisms associated with increased levels of LDL-C or Lp(a) have been genotyped in population cohorts with FH phenotype, to identify the cause of hypercholesterolemia in mutation negative individuals. In different studies, a large proportion of individuals without a monogenic causative variant (in low density lipoprotein receptor gene (LDLR), apolipoprotein B gene (APOB) or proprotein convertase subtilisin/kexin type 9 gene (PCSK9 genes) was considered to have a hypercholesterolemia with a polygenic basis. The heterogeneity in the phenotype of monogenic FH may also be explained by polygenic contributions to LDL-C. The elevated LDL-C genetic risk score (GRS) has been associated with increased risk of atherosclerotic cardiovascular disease in individuals with monogenic FH. Moreover, a poorer response to lipid lowering therapy has been associated with monogenic FH when compared to a polygenic basis. The reason why Lp(a) concentrations are raised in individuals with clinical FH is unclear, but it could be caused by a genetic variation in Lipoprotein(A) gene as a polygenic contribution. Polygenic risk scores have revealed to be important tools to define the cause of hypercholesterolemia in FH mutation-negative individuals and should be included in FH diagnosis strategies, although there is still space for more specific LDL-C GRS to be developed. The use of GRS may be used to refine cardiovascular risk prediction in FH patients and could lead to a personalized approach to therapy. The identification of the genetic status of an individual with FH phenotype (monogenic or polygenic) may have implications on their risk stratification, cascade screening of relatives, disease management and therapeutic measures.

Swiss cost-effectiveness analysis of universal screening for Lynch syndrome of patients with colorectal cancer followed by cascade genetic testing of relatives

BackgroundWe estimated the cost-effectiveness of universal DNA screening for Lynch syndrome (LS) among newly diagnosed patients with colorectal cancer (CRC) followed by cascade screening of relatives from the Swiss healthcare...

Feasibility and cost of FH cascade screening in Belgium (BEL-CASCADE) including a novel rapid rule-out strategy

Background Familial hypercholesterolaemia (FH) is underdiagnosed in most countries. We report our first experience from a national pilot project of cascade screening in relatives of FH patients. Methodology Participating specialists recruited consecutive index patients (IP) with Dutch Lipid Clinic Network (DLCN) score ≥6. After informed consent, the relatives were visited by the nurses to collect relevant clinical data and perform blood sampling for lipid profile measurement. FH diagnosis in the relatives was based on the DLCN and/or MEDPED FH (Make-Early-Diagnosis-to-Prevent-Early-Deaths-in-FH) criteria. Results In a period of 18 months, a total of 127 IP (90 with definite FH and 37 with probable FH) were enrolled in 15 centres. Out of the 270 relatives visited by the nurses, 105 were suspected of having FH: 31 with DCLN score >8, 33 with DLCN score 5-8 and 41 with MEDPED FH criteria. In a post-hoc analysis, another set of MEDPED FH criteria established in the Netherlands and adapted to Belgium allowed to detect FH in 51 additional relatives. Conclusion In a country with no national FH screening program, our pilot project demonstrated that implementing a simple phenotypical FH cascade screening strategy using the collaboration of motivated specialists and two nurses, allowed to diagnose FH in 127 index patients and an additional 105 of their relatives over the two-year period. Newly developed MEDPED FH cut-offs, easily applicable by a nurse with a single blood sample, might further improve the sensitivity of detecting FH within families.

P.(Asp47Asn) and p.(Thr62Met): non deleterious LDL receptor missense variants functionally characterized in vitro

Familial Hypercholesterolemia (FH) is a common genetic disorder caused most often by mutations in the Low Density Lipoprotein Receptor gene (LDLr) leading to high blood cholesterol levels, and ultimately to development of premature coronary heart disease. Genetic analysis and subsequent cascade screening in relatives allow diagnosis of FH at early stage, especially relevant to diagnose children. So far, more than 2300 LDLr variants have been described but only a minority of them have been functionally analysed to evaluate their pathogenicity in FH. Thus, identifying pathogenic mutations in LDLr is a long-standing challenge in the field. In this study, we investigated in vitro the activity p.(Asp47Asn) and p.(Thr62Met) LDLr variants, both in the LR1 region. We used CHO-ldlA7 transfected cells with plasmids carrying p.(Asp47Asn) or p.(Thr62Met) LDLr variants to analyse LDLr expression by FACS and immunoblotting, LDL binding and uptake was determined by FACS and analysis of mutation effects was assessed in silico. The in vitro activity assessment of p.(Asp47Asn) and p.(Thr62Met) LDLr variants shows a fully functional LDL binding and uptake activities. Therefore indicating that the three of them are non-pathogenic LDLr variants. These findings also emphasize the importance of in vitro functional LDLr activity studies to optimize the genetic diagnosis of FH avoiding the report of non-pathogenic variants and possible misdiagnose in relatives if cascade screening is carried out.

Phenotype-driven molecular autopsy for sudden cardiac death.

A phenotype-driven approach to molecular autopsy based in a multidisciplinary team comprising clinical and laboratory genetics, forensic medicine and cardiology is described. Over a 13 year period, molecular autopsy was undertaken in 96 sudden cardiac death cases. A total of 46 cases aged 1-40 years had normal hearts and suspected arrhythmic death. Seven (15%) had likely pathogenic variants in ion channelopathy genes [KCNQ1 (1), KCNH2 (4), SCN5A (1), RyR2(1)]. Fifty cases aged between 2 and 67 had a cardiomyopathy. Twenty-five had arrhythmogenic right ventricular cardiomyopathy (ARVC), 10 dilated cardiomyopathy (DCM) and 15 hypertrophic cardiomyopathy (HCM). Likely pathogenic variants were found in three ARVC cases (12%) in PKP2, DSC2 or DSP, two DCM cases (20%) in MYH7, and four HCM cases (27%) in MYBPC3 (3) or MYH7 (1). Uptake of cascade screening in relatives was higher when a molecular diagnosis was made at autopsy. In three families, variants previously published as pathogenic were detected, but clinical investigation revealed no abnormalities in carrier relatives. With a conservative approach to defining pathogenicity of sequence variants incorporating family phenotype information and population genomic data, a molecular diagnosis was made in 15% of sudden arrhythmic deaths and 18% of cardiomyopathy deaths.

Expert and Advocacy Group Consensus Findings on the Horizon of Public Health Genetic Testing.

Description: Among the two leading causes of death in the United States, each responsible for one in every four deaths, heart disease costs Americans $300 billion, while cancer costs Americans $216 billion per year. They also rank among the top three causes of death in Europe and Asia. In 2012 the University of Michigan Center for Public Health and Community Genomics and Genetic Alliance, with the support of the Centers for Disease Control and Prevention Office of Public Health Genomics, hosted a conference in Atlanta, Georgia to consider related action strategies based on public health genomics. The aim of the conference was consensus building on recommendations to implement genetic screening for three major heritable contributors to these mortality and cost figures: hereditary breast and ovarian cancer (HBOC), familial hypercholesterolemia (FH), and Lynch syndrome (LS). Genetic applications for these three conditions are labeled with a “Tier 1” designation by the U.S. Centers for Disease Control and Prevention because they have been fully validated and clinical practice guidelines based on systematic review support them. Methodology: The conference followed a deliberative sequence starting with nationally recognized clinical and public health presenters for each condition, followed by a Patient and Community Perspectives Panel, working group sessions for each of the conditions, and a final plenary session. The 74 conference participants represented disease research and advocacy, public health, medicine and nursing, genetics, governmental health agencies, and industry. Participants drew on a public health framework interconnecting policy, clinical intervention, surveillance, and educational functions for their deliberations. Results: Participants emphasized the importance of collaboration between clinical, public health, and advocacy groups in implementing Tier 1 genetic screening. Advocacy groups could help with individual and institutional buy-in of Tier 1 programs. Groups differed on funding strategies, with alternative options such as large-scale federal funding and smaller scale, incremental funding solutions proposed. Piggybacking on existing federal breast and colorectal cancer control programs was suggested. Public health departments need to assess what information is now being collected by their state cancer registries. The groups advised that information on cascade screening of relatives be included in toolkits for use by states. Participants stressed incorporation of family history into health department breast cancer screening programs, and clinical HBOC data into state surveillance systems. The carrying out of universal LS screening of tumors in those with colorectal cancer was reviewed. Expansion of universal screening to include endometrial tumors was discussed, as was the application of guidelines recommending cholesterol screening of children 9–11 years old. States more advanced in terms of Tier 1 testing could serve as models and partners with other states launching screening and surveillance programs. A multidisciplinary team of screening program champions was suggested as a means of raising awareness among the consumer and health care communities. Participants offered multiple recommendations regarding use of electronic health records, including flagging of at-risk family members and utilization of state-level health information exchanges. The paper contains an update of policy developments and happenings for all three Tier 1 conditions, as well as identified gaps. Conclusions: Implementation of cascade screening of family members for HBOC and FH, and universal screening for LS in CRC tumors has reached a point of readiness within the U.S., with creative solutions at hand. Facilitating factors such as screening coverage through the Patient Protection and Affordable Care Act, and state health information exchanges can be tapped. Collaboration is needed between public health departments, health care systems, disease advocacy groups, and industry to fully realize Tier 1 genetic screening. State health department and disease networks currently engaged in Tier 1 screening can serve as models for the launch of new initiatives.

Genetic Etiology and Evaluation of Sudden Cardiac Death

A wide range of inherited syndromes can result in ventricular arrhythmias and sudden cardiac death (SCD). The natural histories of inherited arrhythmia syndromes are highly variable and current risk stratification techniques are limited. Thus, the management of these conditions can be difficult and often involves a combination of risk assessment, lifestyle modification, cardiac interventions, counselling, and family screening. Recent advances in high throughput sequencing have enabled routine testing in patients with a high clinical index of suspicion for an inherited arrhythmia condition, and cascade screening in relatives of mutation carriers. Given the complexity in screening and data interpretation that has been introduced by recent genomic advances, individuals with inherited arrhythmia syndromes are encouraged to seek care at specialized centers with cardiovascular genetics expertise. In this review, we discuss the etiologies of SCD syndromes and discuss strategies for the evaluation of patients at risk for SCD with a focus on the role of genetic testing and family screening.

Pacemaker implantation in a patient with brugada and sick sinus syndrome

Brugada syndrome (BrS) is a rare and inherited primary arrhythmic syndrome characterized by ST-segment elevations in the right precordial leads (V1-V3) with an increased risk of sudden cardiac death (SCD). Arrhythmias in BrS are often nocturne, and brady-arrhythmias are often seen in patients with loss-of-function mutations in SCN5A. In this case-report we present a 75-year old woman referred to our outpatient clinic for inherited cardiac diseases for a familial clinical work-up. Since childhood she had suffered from dizziness, absence seizures, and countless Syncope's. In 2004 sick sinus syndrome was suspected and she was treated with implantation of a pacemaker (PM) at another institution. An inherited cardiac disease was one day suddenly suspected, as the patient had a 61-year old brother who was diagnosed with symptomatic BrS, and treated with an implantable cardioverter defibrillator (ICD) after aborted SCD. A mutation screening revealed a SCN5A [S231CfsX251 (c.692-693delCA)] loss-of-function mutation not previously reported, and as a part of the cascade screening in relatives she was therefore referred to our clinic. In the 7 year period after PM implantation she had experienced no cardiac symptoms, although her electrocardiogram changes now were consistent with a BrS type 1 pattern. A genetic test confirmed that she had the same mutation in SCN5A as her brother. In this case-report we present a loss-of function mutation in SCN5A not previously associated with BrS nor presented in healthy controls. Sinus node dysfunction has previously been documented in patients with symptomatic BrS, which suggests it is not a rare concomitant. The only accepted treatment of BrS is today implantation of an ICD. In the future studies should evaluate if PM in some cases of symptomatic BrS can be used instead of ICDs in patients with a loss-of-function SCN5A mutations.

Finding the proverbial “needle in a haystack”: Identifying presymptomatic individuals with long QT syndrome

Spanish author Miguel de Cervantes (1547–1616) is credited as the originator of many phrases and proverbs that persist to this day, several of which are eminently suitable for consideration (and repetition) by electrophysiologists. As an example, Don Quixote’s misguided attempt to attack a group of windmills (that he believed to be malevolent giants) cautions us against “tilting at windmills” when we consider a challenging procedure with uncertain benefit. In the passage that provides the epigram above, Don Quixote’s longsuffering squire, Sancho Panza, likened his master’s fruitless quests to finding “a needle in a bottle [bundle] of hay” and comforted himself with the thought that, other than death, all his troubles may be remedied, eventually. Presymptomatic patients with long QT syndrome (LQTS) are (along with other inherited heart rhythm disorders) the “needles” in the haystack of the general population that modern-day cardiologists would like to find and treat before their first, potentially serious or lethal, episode of arrhythmia. In recent years, there has been growing interest in the use of electrocardiogram (ECG) screening to identify such patients, although the feasibility of this measure remains the subject of study. In this issue of HeartRhythm, Earle et al present an “alternative” approach to the problem by applying cascade screening in relatives of LQTS probands enrolled in the New Zealand Cardiac Inherited Disease Registry. Four decades ago, the presymptomatic detection of Huntington disease was first achieved through provocative drug challenge of first-degree relatives of diagnosed patients, not unlike our current use of sodium channel blockers to unmask Brugada syndrome. This early phenotypic testing was eventually followed, 20 years later, by genetic testing. However, the ability to diagnose (at high certainty) a progressive, debilitating, untreatable, and eventually fatal disorder created challenges for physicians, genetics counselors, and medical ethicists that continue to be worthy of our attention as we consider how to approach the identification of

Sudden cardiac death in young athletes

Athletic activity is associated with an increased risk of sudden death for individuals with some congenital or acquired heart disorders. This review considers in particular the causes of death affecting athletes below 35 years of age. In this age group the largest proportion of deaths are caused by diseases with autosomal dominant inheritance such as hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, long QT-syndrome, and Marfan’s syndrome. A policy of early cascade-screening of all first-degree relatives of patients with these disorders will therefore detect a substantial number of individuals at risk. A strictly regulated system with preparticipation screening of all athletes following a protocol pioneered in Italy, including school-age children, can also detect cases caused by sporadic new mutations and has been shown to reduce excess mortality among athletes substantially. Recommendations for screening procedure are reviewed. It is concluded that ECG screening ought to be part of preparticipation screening, but using criteria that do not cause too many false positives among athletes. One such suggested protocol will show positive in approximately 5% of screened individuals, among whom many will be screened for these diseases. On this point further research is needed to define what kind of false-positive and false-negative rate these new criteria result in. A less formal system based on cascade-screening of relatives, education of coaches about suspicious symptoms, and preparticipation questionnaires used by athletic clubs, has been associated over time with a sizeable reduction in sudden cardiac deaths among Swedish athletes, and thus appears to be worth implementing even for junior athletes not recommended for formal preparticipation screening. It is strongly argued that in families with autosomal dominant disorders the first screening of children should be carried out no later than 6 to 7 years of age.

Update of the Portuguese Familial Hypercholesterolaemia Study

The main aim of the Portuguese Familial Hypercholesterolaemia Study is to identify the genetic cause of hypercholesterolaemia in individuals with a clinical diagnosis of Familial Hypercholesterolaemia (FH). A total of 1340 blood samples were collected from 482 index patients and 858 relatives with the collaboration of clinicians from several hospitals all over the country. The genetic diagnosis of FH in this study is based on the analyses of three genes: LDLR, APOB and PCSK9. In the last 10 years, the Portuguese FH Study identified a genetic defect in a total of 171 index patients, corresponding to an overall of 48% of the total received cases with clinical diagnosis of FH. Although the Simon Broome FH register criteria have been adapted to our study, 59 patients that did not fulfil all criteria were included in the study and a mutation causing disease was identified in 8 of these patients. In the LDLR gene were found 80 different mutations in 165 unrelated index patients: 159 heterozygous, 3 compounds heterozygous and 3 true homozygous. The APOB p.Arg3527Gln and the PCSK9 p.Asp374His mutation were not found in any of our patients since our last report, but a novel mutation in the APOB gene, predicted to cause a single amino acid substitution p.Tyr3560Cys, was found in one patient. The cascade screening in relatives of these 171 index patients allowed the identification and genetic characterization of a total of 404 FH patients in Portugal.

Regulation of the LDL receptor in familial hypercholesterolemia

Dysregulation of the LDL receptor pathway causes the inherited metabolic disorder familial hypercholesterolemia, characterized by raised serum LDL and increased risk of coronary heart disease. Defects in the LDL receptor gene itself are the most frequent cause, and identification of the genetic defect is now considered a useful adjunct to clinical diagnosis, although care must be taken to ensure the variant is causal. Familial hypercholesterolemia is underdiagnosed, and although population screening is not considered cost effective, cascade screening of relatives of affected patients is underway and should allow effective preventative treatment. Defects in other genes can cause a very similar phenotype, for example, the genes for apolipoprotein B, the ligand for the LDL receptor, ARH, a protein essential for internalization of the receptor from the cell surface, and PCSK9, a protein that increases degradation of LDL receptor protein. Not all clinically diagnosed patients have a known defect suggesting tha...

The Clinical Relevance of Compound Heterozygosity for the C282Y and H63D Substitutions in Hemochromatosis

Two major mutations are defined within the hemochromatosis gene, HFE. Although the effects of the C282Y substitution have been well characterized, the clinical significance of the C282Y/H63D state remains unclear. This study assessed the phenotypic expression in C282Y/H63D subjects as compared with C282Y homozygotes. Data were obtained from 91 C282Y/H63D probands, 158 C282Y/H63D subjects identified through family screening, and 483 C282Y homozygotes. Subjects underwent clinical evaluation, genotyping, biochemical assessment, and liver biopsy examination where clinically indicated. C282Y/H63D probands had significantly less clinical and biochemical expression than C282Y homozygotes. Biochemical expression was higher in C282Y/H63D probands than in C282Y/H63D subjects identified through family screening (P < .001). Of the C282Y/H63D subjects with serum ferritin levels greater than 1000 mug/L, all had known comorbid factors that could have contributed to the increased ferritin level. Of the 51 C282Y/H63D subjects who underwent liver biopsy examination, significantly increased iron stores were present in 9 subjects and hepatic fibrosis was present in 13. Twelve of the 13 had evidence of hepatic steatosis, excess alcohol consumption, or diabetes. The mobilizable iron level was significantly higher in C282Y homozygous males than in compound heterozygous males (P < .001). Genetic screening of C282Y/H63D first-degree relatives detected 5 C282Y homozygotes. C282Y/H63D subjects referred for assessment had a high prevalence of increased iron indices but did not develop progressive clinical disease without comorbid factors such as steatosis, diabetes, or excess alcohol consumption. When fibrosis was seen, 1 or more comorbid factors almost always were present. Thus, phlebotomy therapy is warranted and cascade screening of relatives should be performed because expressing C282Y homozygotes may be detected.