Eligible First-degree Relatives Research Articles

Cascade testing in mitochondrial diseases: a cross-sectional retrospective study

BackgroundCascade testing can offer improved surveillance and timely introduction of clinical management for the at-risk biological relatives. Data on cascade testing and costs in mitochondrial diseases are lacking. To address this gap, we performed a cross-sectional retrospective study to provide a framework for cascade testing in mitochondrial diseases, to estimate the eligibility versus real-time uptake of cascade testing and to evaluate the cost of the genetic diagnosis of index cases and the cost of predictive cascade testing.MethodsData was collected through retrospective chart review. The variant inheritance pattern guided the identification of eligible first-degree relatives: (i) Males with mitochondrial DNA (mtDNA) single nucleotide variants (SNVs) – siblings and mothers. (ii) Females with mtDNA SNVs – siblings, mothers and offspring. (iii) Autosomal Dominant (AD) nuclear DNA (nDNA) variants – siblings, offspring and both parents. (iv) Autosomal Recessive (AR) nDNA variants – siblings.ResultsWe recruited 99 participants from the Adult Mitochondrial Disease Clinic in Sydney. The uptake of cascade testing was 55.2% in the mtDNA group, 55.8% in the AD nDNA group and 0% in AR nDNA group. Of the relatives in mtDNA group who underwent cascade testing, 65.4% were symptomatic, 20.5% were oligosymptomatic and 14.1% were asymptomatic. The mean cost of cascade testing for eligible first-degree relatives (mtDNA group: $694.7; AD nDNA group: $899.1) was lower than the corresponding index case (mtDNA group: $4578.4; AD nDNA group: $5715.1) (p < 0.001).ConclusionThe demand for cascade testing in mitochondrial diseases varies according to the genotype and inheritance pattern. The real-time uptake of cascade testing can be influenced by multiple factors. Early diagnosis of at-risk biological relatives of index cases through cascade testing, confirms the diagnosis in those who are symptomatic and facilitates implementation of surveillance strategies and clinical care at an early stage of the disease.

Genetic testing and family screening in idiopathic pediatric cardiomyopathy: a prospective observational study from a tertiary care center in North India

IntroductionThere are limited data on family screening and genetic testing in pediatric cardiomyopathy from India. This study was conducted to describe the morphologic spectrum and identify potential familial and genetic causes of pediatric cardiomyopathies in this region.MethodsFrom April 2018 to May 2020, all children from birth to 18 years of age with cardiomyopathy visiting a tertiary care hospital in North India were enrolled in this study. First-degree relatives of index patients were offered screening for cardiomyopathy; 260 clinically reported pathogenic/likely pathogenic variants in 17 genes were analyzed by a rapid genotyping method. Additionally, a subset of patients also underwent whole-exome sequencing.ResultsOf the 20 patients enrolled in this study (median age 42 months), 18 were clinically diagnosed with dilated cardiomyopathy. We observed a 44.4% mortality rate after a median follow-up of 15 months. 61.3% of the eligible first-degree relatives underwent screening, and one patient was identified to have familial cardiomyopathy. Multi-panel gene testing was performed on 18 patients, and none were found to have a pathogenic or likely pathogenic variant; 9 patients also underwent whole-exome sequencing, and pathogenic and likely pathogenic variants were identified in 50% (4/8) of them.ConclusionDilated cardiomyopathy is the most common morphologic form of pediatric cardiomyopathy in India and has a high mortality rate. The prevalence of familial cardiomyopathy was low in this study. Future studies should evaluate the role of whole-exome sequencing in identifying genetic causes of cardiomyopathy in children.

Genetic testing in families with hereditary colorectal cancer in British Columbia and Yukon: a retrospective cross-sectional analysis.

Genetic testing in families with hereditary cancer enables identification of people most likely to benefit from intensive screening and preventive measures; however, the uptake of testing in relatives (known as cascade carrier testing) for hereditary colorectal cancer syndromes has been shown to be low. Our objective was to report rates of familial testing for hereditary colorectal cancer syndromes in a publicly funded hereditary cancer clinic in Canada. A cross-sectional retrospective database review was used to determine testing uptake between 1997 and 2016 for families served by the provincial Hereditary Cancer Program for British Columbia and Yukon. Analyses were conducted for genes associated with syndromes with an increased risk for colorectal cancer, including Lynch syndrome (MLH1, MSH2, MSH6, PMS2 and EPCAM) and familial adenomatous polyposis (APC), and for additional moderate- to high-penetrance genes (STK11, TP53, SMAD4, MUTYH, PTEN and CHEK2). Descriptive statistics were used and all analyses were 2-tailed. The study cohort included 245 index patients, with carrier testing performed in 382 relatives. The mean age at family member testing was 41.2 years, and most (61.0%) of the family members who underwent testing were women. The median time between disclosure of index cases and their family member's results was 8.3 months. Among eligible first-degree relatives, 32.6% (268/821) underwent testing in BC. Of 67 cancer diagnoses in family members, most (62.7%) occurred before genetic testing. A substantial proportion of people at risk for hereditary colorectal cancer do not undergo genetic testing. This gap highlights the need to explore barriers to testing and to consider interventions to promote uptake; more aggressive efforts by hereditary cancer programs are needed to reach this highest risk population.

Barriers to participation in cancer prevention clinical trials

Background. Cancer prevention clinical trials seek to enroll individuals at increased risk for cancer. Little is known about attitudes among physicians and at-risk individuals towards cancer prevention clinical trials. We sought to characterize barriers to prevention trial participation among medical oncologists and first-degree relatives of their patients. Methods. Physician participants were practicing oncologists in Pennsylvania. Eligible first-degree participants were adult relatives of a cancer patient being treated by one of the study physicians. The influence of perceived psychosocial and practical barriers on level of willingness to participate in cancer prevention clinical trials was investigated. Results. Response rate was low among physicians, 137/478 (29%), and modest among eligible first-degree relatives, 82/129 (64%). Lack of access to an eligible population for prevention clinical trials was the most commonly cited barrier to prevention clinical trials among oncologists. Nearly half (45%) of first-degree relatives had not heard of cancer prevention clinical trials, but 68% expressed interest in learning more, and 55% expressed willingness to participate. In the proportional odds model, greater information source seeking/responsiveness (i.e., interest in learning more about clinical prevention trials from more information sources) (p = 0.04), and having fewer psychosocial barriers (p = 0.02) were associated with a greater willingness to participate. Conclusions. Many individuals who may be at greater risk for developing cancer because of having a first-degree relative with cancer are unaware of the availability of clinical cancer prevention trials. Nonetheless, many perceive low personal risk associated with these studies, and are interested in learning more.

Long-term Evaluation of Three Multiple-Case Waldenström Macroglobulinemia Families

Because the clinical significance of immunoglobulin abnormalities reported in relatives of familial Waldenström macroglobulinemia (WM) patients is unknown, we initiated a follow-up study of three WM families originally evaluated 27 years previously. Of 29 eligible first-degree relatives of WM patients, 27 (93%) had originally participated in clinical and electrophoretic evaluations. We re-contacted all participants for prospective follow-up electrophoretic analysis and other studies. Initially, five relatives had IgM monoclonal gammopathy (IgM MG), and four had IgM polyclonal gammopathy (PG). Twenty-two relatives (81%) were re-evaluated. Median follow-up was 17 years (range, 7-27). At re-contact, all IgM MG persisted or progressed, including three that evolved to WM. Among the four with PG, two new IgM MG cases developed. Overall, seven relatives (26%) had IgM MG, and five (18%) had IgM PG. Although based on small numbers, this study provides the longest comprehensive follow-up of WM families to date. IgM MG seems to be a phenotypic marker of WM susceptibility in some families and may have a high risk of progression to WM. IgM PG may also be important in WM families. These observations require validation in larger studies and, if confirmed, may be used to identify a cohort (relatives with IgM MG) for future prevention strategies.

Genetic counseling and testing in families with hereditary nonpolyposis colorectal cancer.

Genetic testing to refine cancer risk is available. However, little is known about factors affecting the uptake of testing for the most common hereditary colon cancer, hereditary nonpolyposis colorectal cancer. This study investigated attitudes, intentions, and uptake of genetic testing within newly identified families with hereditary nonpolyposis colorectal cancer. Cohort study conducted at the National Institutes of Health between April 15, 1996, and November 20, 1999. Data were collected through questionnaires before semistructured education sessions, individual counseling sessions, and the offer of genetic testing. Of the 111 eligible first-degree relatives, 51% chose to participate in education and individual counseling sessions. Participation was associated with greater numbers of first-degree relatives with cancer; no association was found between participation and personal history of cancer. Before education and individual counseling sessions, 64% of participants had heard little about genetic testing for cancers; however, most (97%) stated intentions to pursue testing. Fifty-one percent identified learning about their children's risks as the most important reason to consider testing. Thirty-nine percent identified the potential effect on their health insurance as the most important reason to not undergo testing. Of the 111 eligible first-degree relatives, 51% chose to undergo genetic testing. Participants' intentions to pursue genetic testing were significantly affected by concerns regarding the ability to handle the emotional aspects of testing and the psychosocial effect on family members. Genetic counseling and testing offers the potential to focus cancer screening resources in individuals truly at increased risk, thereby reducing mortality and morbidity. Fears of discrimination and concerns about psychological and psychosocial issues may present barriers to the use of current cancer prevention strategies, including genetic counseling and testing.

Worry and attitude of men in at-risk families for prostate cancer about genetic susceptibility and genetic testing.

The aim of this study was to evaluate worry about genetic susceptibility and the attitude of men with family history of prostate cancer (CaP) toward genetic testing. Three hundred seventy-five eligible first-degree relatives (FDR) of men with CaP, were asked to participate in a screening and to fill out a survey covering the worry about genetic susceptibility and interest in genetic testing. Of the 375 candidates contacted, 277 completed the survey, and had undergone PSA measurement. Sixty-four percent worried a little or not at all about inherited predisposition to CaP, while the remainder worried a lot or extremely. The candidates who worried a lot or extremely were men with high levels of durable anxiety disposition (STAI trait), who had undergone a previous screening procedure and men with sons. Ninety-eight percent of men expressed their interest in undergoing genetic testing. The most motivated candidates to have the test done were men with several relatives with CaP. The level of worry about genetic susceptibility was low and there was a concrete interest in genetic testing in FDR of men with CaP. This interest increased with the number of CaP in the family.

Is the genetic liability in multifactorial disorders higher in concordant than discordant monozygotic twin pairs? A population-based family twin study of migraine without aura.

Migraine without aura (MO) is a multifactorial disorder. Expression of a disorder with multifactorial inheritance depends on the genetic liability and on environmental factors. A high liability is reflected by a high frequency of affected relatives. We have previously shown that monozygotic (MZ) twin pairs have a significant higher concordance of MO than dizygotic twin pairs. The incomplete concordance among MZ twin pairs may be due to a lower genetic liability among discordant than concordant MZ twin pairs. The present study analysed the genetic liability in MZ twin pairs concordant and discordant for MO by the population-relative risk of MO among parents and siblings. The twin pairs were from the population-based Danish Twin Register. First-degree relatives of 29 concordant and 34 discordant MZ twin pairs were blindly telephone interviewed by a physician. The participation rate of the eligible first-degree relatives was 96%. The population-relative risk of MO among parents and siblings was 2.73 (2.39-3.06) in concordant and 2.37 (2.03-2.71) in discordant MZ twin pairs. The relative risk of MO was significantly higher in female first-degree relatives of concordant than of discordant MZ male and female twin pairs. An opposite effect was observed in male first-degree relatives, although this was not significant for male first-degree relatives of female MZ twin pairs. The present study found no statistically significant difference in genetic liability to MO among concordant and discordant MZ twin pairs. However, a difference in genetic liability among MZ and DZ twin pairs is anticipated to be small. Thus, it may be possible to show the effect in a larger study population or by investigating a more frequent trait than MO.