Using implementation science to evaluate a population-wide genomic screening program: Findings from the first 20,000 In Our DNA SC participants.

We use the implementation science framework RE-AIM (reach, effectiveness, adoption, implementation, and maintenance) to describe outcomes of In Our DNA SC, a population-wide genomic screening (PWGS) program. In Our DNA SC involves participation through clinical appointments, community events, or at home collection. Participants provide a saliva sample that is sequenced by Helix, and those with a pathogenic variant or likely pathogenic variant for CDC Tier 1 conditions are offered free genetic counseling. We assessed key outcomes among the first cohort of individuals recruited. Over 14 months, 20,478 participants enrolled, and 14,053 samples were collected. The majority selected at-home sample collection followed by clinical sample collection and collection at community events. Participants were predominately female, White (self-identified), non-Hispanic, and between the ages of 40-49. Participants enrolled through community events were the most racially diverse and the youngest. Half of those enrolled completed the program. We identified 137 individuals with pathogenic or likely pathogenic variants for CDC Tier 1 conditions. The majority (77.4%) agreed to genetic counseling, and of those that agreed, 80.2% completed counseling. Twelve clinics participated, and we conducted 108 collection events. Participants enrolled at home were most likely to return their sample for sequencing. Through this evaluation, we identified facilitators and barriers to implementation of our state-wide PWGS program. Standardized reporting using implementation science frameworks can help generalize strategies and improve the impact of PWGS.

Applying the R = MC2 implementation science heuristic to assess the impact of readiness on reach and implementation of a population-wide genomic screening program.

Population-wide genomic screening for genes that have high penetrance and clinical actionability enhances the opportunity to identify individuals at risk for developing hereditary conditions. Organizational readiness has been shown to influence the likelihood of successful implementation of complex initiatives such as the integration of population-wide genomic screening in clinical settings. We use the organizational readiness heuristic R = MC2 to better understand three factors that influence readiness for implementation of In Our DNA SC, a population-wide genomic screening program: motivation to implement, general capacity of an organization, and innovation-specific capacities. We then assessed the influence of these readiness factors on implementation outcomes of reach (measured through enrollment rate) and implementation (measured through the number of DNA samples collected). Data were collected pre-implementation and captured during the three-month pilot phase of the In Our DNA SC program. We collected administrative data from the electronic health record and quantitatively captured elements of readiness through surveys distributed to provider champions and clinical administrative champions at the 10 sites implementing the population-wide genomic screening program. We facilitated innovation-specific capacity through training offered at each site, as well as technical assistance through weekly meetings with other implementing sites, and resources available to all staff. Forty percent of provider champions attended training and 80% of administrative champions attended training. An average of 3.7 additional staff were trained at each implementing site. Satisfaction with training positively influenced reach (ß = 0.0121, p = 0.0271) but did not impact implementation. Provider engagement (innovation capabilities) was associated with reach (ß = 0.0020, p = 0.0251) and clinical administrator engagement was associated with sample collection rate (ß = 0.2599, ß = 0.038). Readiness to change is considered one of the most important factors in understanding the potential opportunity for implementation. We found that motivation to adopt a population-wide genomic screening program positively impacted the program's reach. The type of champion influenced discrete outcomes, with provider champions positively impacting reach and administrative champions influencing implementation (assessed through sample collection rate). As genomics continues to be integrated into clinical practice, it will be important to understand the contextual factors that influence readiness for implementation and design support throughout the life-course of implementation to ensure the success of large-scale, complex initiatives.

Enteric methane emission estimates for the Zimbabwean Sanga cattle breeds of Tuli and Mashona.

The effectiveness of methane mitigation in ruminant livestock production systems depends on the accuracy of estimating methane emission factors and providing accurate emission inventories. Following the Paris Climate agreement, it is recommended that countries adopt the Tier-2 approach for estimating enteric methane emissions from ruminants instead of the Tier-1 approach currently used by most countries. This study sought to provide base line enteric methane emission estimates for the Tuli and Mashona Sanga cattle breeds in Zimbabwe using the IPCC Tier-2 model. Using animal characterization data collected from 412 cattle from Grasslands Research Institute and 406 cattle from Makoholi Research Institute, net energy requirements were estimated. From this and the estimate for digestibility, gross energy intake and dry matter intake were estimated. Gross energy intakes and the estimated methane conversion factor were used to estimate enteric methane emissions. Mean emission factors for Tuli were 45.1, 56, 28.5, 28.4 and 20.6 kg CH4/head/year for cows, bulls, heifers, steers and calves, respectively. For Mashona, they were 47.8, 51.9, 29, 29.1 and 20.7 kgCH4/head/year for cows, bulls, heifers, steers and calves, respectively. Generally, estimated Tier-2 emission factors were significantly different from the IPCC Tier-1 default emission factors. This study concluded that enteric methane emission factors estimated using the IPCC Tier-2 model offer insights into the controversial use of the default IPCC Tier-1 emission factors.

Burkholderia pseudomallei JW270 Is Lethal in the Madagascar Hissing Cockroach Infection Model and Can Be Utilized at Biosafety Level 2 to Identify Putative Virulence Factors.

Burkholderia pseudomallei, the causative agent of melioidosis, is classified by the CDC as a tier 1 select agent, and work involving it must be performed in a biosafety level 3 (BSL-3) laboratory. Three BSL-2 surrogate strains derived from B. pseudomallei 1026b, a virulent clinical isolate, have been removed from the CDC select agent list. These strains, Bp82, B0011, and JW270, are highly attenuated in rodent models of melioidosis and cannot be utilized to identify virulence determinants because of their high 50% lethal dose (LD50). We previously demonstrated that the Madagascar hissing cockroach (MHC) is a tractable surrogate host to study the innate immune response against Burkholderia. In this study, we found that JW270 maintains its virulence in MHCs. This surprising result indicates that it may be possible to identify potential virulence genes in JW270 by using MHCs at BSL-2. We tested this hypothesis by constructing JW270 mutations in genes that are required (hcp1) or dispensable (hcp2) for B. pseudomallei virulence in rodents. JW270 Δhcp1 was avirulent in MHCs and JW270 Δhcp2 was virulent, suggesting that MHCs can be used at BSL-2 for the discovery of important virulence factors. JW270 ΔBPSS2185, a strain harboring a mutation in a type IV pilin locus (TFP8) required for full virulence in BALB/c mice, was also found to be attenuated in MHCs. Finally, we demonstrate that the hmqA-G locus, which encodes the production of a family of secondary metabolites called 4-hydroxy-3-methyl-2-alkylquinolines, is important for JW270 virulence in MHCs and may represent a novel virulence determinant.

Formaldehyde and Glutaraldehyde Inactivation of Bacterial Tier 1 Select Agents in Tissues.

For safety, designated Select Agents in tissues must be inactivated and viability tested before the tissue undergoes further processing and analysis. In response to the shipping of samples of "inactivated" Bacillus anthracis that inadvertently contained live spores to nonregulated entities and partners worldwide, the Federal Register now mandates in-house validation of inactivation procedures and standardization of viability testing to detect live organisms in samples containing Select Agents that have undergone an inactivation process. We tested and validated formaldehyde and glutaraldehyde inactivation procedures for animal tissues infected with virulent B. anthracis, Burkholderia pseudomallei, Francisella tularensis, and Yersinia pestis. We confirmed that our fixation procedures for tissues containing these Tier 1 Select Agents resulted in complete inactivation and that our validated viability testing methods do not interfere with detection of live organisms. Institutions may use this work as a guide to develop and conduct their own testing to comply with the policy.

The importance of considering animal body mass in IPCC greenhouse inventories and the underappreciated role of wild herbivores.

Methane is an important greenhouse gas, but characterizing production by source sector has proven difficult. Current estimates suggest herbivores produce ~20% (~76-189 Tg yr(-1) ) of methane globally, with wildlife contributions uncertain. We develop a simple and accurate method to estimate methane emissions and reevaluate production by wildlife. We find a strikingly robust relationship between body mass and methane output exceeding the scaling expected by differences in metabolic rate. Our allometric model gives a significantly better fit to empirical data than IPCC Tier 1 and 2 calculations. Our analysis suggests that (i) the allometric model provides an easier and more robust estimate of methane production than IPCC models currently in use; (ii) output from wildlife is much higher than previously considered; and (iii) because of the allometric scaling of methane output with body mass, national emissions could be reduced if countries favored more, smaller livestock, over fewer, larger ones.

Analysis of EPA's endocrine screening battery and recommendations for further review.

EPA's Endocrine Disruptor Screening Program Tier 1 battery consists of eleven assays intended to identify the potential of a chemical to interact with the estrogen, androgen, thyroid, or steroidogenesis systems. We have collected control data from a subset of test order recipients from the first round of screening. The analysis undertaken herein demonstrates that the EPA should review all testing methods prior to issuing further test orders. Given the frequency with which certain performance criteria were violated, a primary focus of that review should consider adjustments to these standards to better reflect biological variability. A second focus should be to provide detailed, assay-specific direction on when results should be discarded; no clear guidance exists on the degree to which assays need to be re-run for failing to meet performance criteria. A third focus should be to identify permissible differences in study design and execution that have a large influence on endpoint variance. Experimental guidelines could then be re-defined such that endpoint variances are reduced and performance criteria are violated less frequently. It must be emphasized that because we were restricted to a subset (approximately half) of the control data, our analyses serve only as examples to underscore the importance of a detailed, rigorous, and comprehensive evaluation of the performance of the battery.

Pesticide sorption and leaching potential on three Hawaiian soils.

On the Hawaiian Islands, groundwater is the principal source of potable water and contamination of this key resource by pesticides is of great concern. To evaluate the leaching potential of four weak acid herbicides [aminocyclopyrachlor, picloram, metsulfuron-methyl, biologically active diketonitrile degradate of isoxaflutole (DKN)] and two neutral non-ionizable herbicides [oxyfluorfen, alachlor], their sorption coefficients were determined on three prevalent soils from the island of Oahu. Metsulfuron-methyl, aminocylcopyrachlor, picloram, and DKN were relatively low sorbing herbicides (K(oc) = 3-53 mL g(-1)), alachlor was intermediate (K(oc) = 120-150 mL g(-1)), and oxyfluorfen sorbed very strongly to the three soils (K(oc) > 12,000 mL g(-1)). Following determination of K(oc) values, the groundwater ubiquity score (GUS) indices for these compounds were calculated to predicted their behavior with the Comprehensive Leaching Risk Assessment System (CLEARS; Tier-1 methodology for Hawaii). Metsulfuron-methyl, aminocyclopyrachlor, picloram, and DKN would be categorized as likely leachers in all three Hawaiian soils, indicating a high risk of groundwater contamination across the island of Oahu. In contrast, oxyfluorfen, regardless of the degradation rate, would possess a low and acceptable leaching risk due to its high sorption on all three soils. The leaching potential of alachlor was more difficult to classify, with a GUS value between 1.8 and 2.8. In addition, four different biochar amendments to these soils did not significantly alter their sorption capacities for aminocyclopyrachlor, indicating a relatively low impact of black carbon additions from geologic volcanic inputs of black carbon. Due to the fact that pesticide environmental risks are chiefly dependent on local soil characteristics, this work has demonstrated that once soil specific sorption parameters are known one can assess the potential pesticide leaching risks.

Key learnings from performance of the U.S. EPA Endocrine Disruptor Screening Program (EDSP) Tier 1 in vitro assays.

Tier 1 of the U.S. EPA Endocrine Disruptor Screening Program comprises 11 studies: five in vitro assays, four in vivo mammalian assays, and two in vivo nonmammalian assays. The battery is designed to detect compounds with the potential to interact with the estrogen, androgen, or thyroid signaling pathways. This article examines the procedures, results, and data interpretation for the five Tier 1 in vitro assays: estrogen receptor (ER) and androgen receptor binding assays, an ER transactivation assay, an aromatase assay, and a steroidogenesis assay. Data are presented from two laboratories that have evaluated approximately 11 compounds in the Tier 1 in vitro assays. Generally, the ER and androgen receptor binding assays and the aromatase assay showed good specificity and reproducibility. As described in the guideline for the ER transactivation assay, a result is considered positive when the test compound induces a reporter gene signal that reaches 10% of the response seen with 1 nM 17ß-estradiol (positive control). In the experience of these laboratories, this cutoff criterion may result in false-positive responses. For the steroidogenesis assay, there is variability in the basal and stimulated production of testosterone and estradiol by the H295R cells. This variability in responsiveness, coupled with potential cell stress at high concentrations of test compound, may make it difficult to discern whether hormone alterations are specific steroidogenesis alterations (i.e., endocrine active). Lastly, both laboratories had difficulty meeting some recommended performance criteria for each Tier 1 in vitro assay. Data with only minor deviations were deemed valid.

PBTK modelling platforms and parameter estimation tools to enable animal-free risk assessment: recommendations from a joint EPAA--EURL ECVAM ADME workshop.

Information on toxicokinetics is critical for animal-free human risk assessment. Human external exposure must be translated into human tissue doses and compared with in vitro actual cell exposure associated to effects (in vitro-in vivo comparison). Data on absorption, distribution, metabolism and excretion in humans (ADME) could be generated using in vitro and QSAR tools. Physiologically-based toxicokinetic (PBTK) computer modelling could serve to integrate disparate in vitro and in silico findings. However, there are only few freely-available PBTK platforms currently available. And although some ADME parameters can be reasonably estimated in vitro or in silico, important gaps exist. Examples include unknown or limited applicability domains and lack of (high-throughput) tools to measure penetration of barriers, partitioning between blood and tissues and metabolic clearance. This paper is based on a joint EPAA--EURL ECVAM expert meeting. It provides a state-of-the-art overview of the availability of PBTK platforms as well as the in vitro and in silico methods to parameterise basic (Tier 1) PBTK models. Five high-priority issues are presented that provide the prerequisites for wider use of non-animal based PBTK modelling for animal-free chemical risk assessment.

Development of a novel sandwich immunoassay based on targeting recombinant Francisella outer membrane protein A for the diagnosis of tularemia.

Introduction: Tularemia, caused by the bacterium Francisella tularensis, poses health risks to humans and can spread through a variety of routes. It has also been classified as a Tier 1 Select agent by the CDC, highlighting its potential as a bioterrorism agent. Moreover, it is difficult to diagnose in a timely fashion, owing to the non-specific nature of tularemia infections. Rapid, sensitive, and accurate detection methods are required to reduce mortality rates. We aimed to develop antibodies directed against the outer membrane protein A of F. tularensis (FopA) for rapid and accurate diagnosis of tularemia. Methods: We used a baculovirus insect cell expression vector system to produce the FopA antigen and generate anti-FopA antibodies through immunization of BALB/c mice. We then employed hybridoma and phage display technologies to screen for antibodies that could recognize unique epitopes on FopA. Result: Two monoclonal antibodies, 6B12 and 3C1, identified through phage display screening specifically bound to recombinant FopA in a dose-dependent manner. The binding affinity of the anti-FopA 6B12 and 3C1 antibodies was observed to have an equilibrium dissociation constant of 1.76 × 10-10 M and 1.32 × 10-9 M, respectively. These antibodies were used to develop a sandwich ELISA system for the diagnosis of tularemia. This assay was found to be highly specific and sensitive, with detection limits ranging from 0.062 ng/mL in PBS to 0.064 ng/mL in skim milk matrices. Discussion: Our findings demonstrate the feasibility of a novel diagnostic approach for detecting F. tularensis based on targeting FopA, as opposed to existing tests that target the bacterial lipopolysaccharide.

Practical Considerations for Navigating Withdrawal from the Federal Select Agent Program.

Introduction: Clear guidance is provided by the Federal Select Agent Program (FSAP) to assist registered entities in nearly all facets of compliance with the Federal select agent regulations (7 CFR Part 331; 9 CFR Part 121; 42 CFR Part 73). If a registered entity chooses to discontinue its registration, detailed instructions for registration withdrawal are deeply embedded within a document entitled "eFSAP Form 1 Amendment Instructions," which is found on the FSAP website within the electronic Federal Select Agent Program (eFSAP) Resource Center. Methods: Using the information found within the eFSAP Form 1 Amendment Instructions, as well as extensive written and verbal guidance provided by the lead assigned entity point of contact at the FSAP, we completed the FSAP withdrawal process during a 12-month period between 2022 and 2023. Discussion: This commentary shares our recent professional experiences navigating the FSAP withdrawal process at the University of Texas Health Science Center at Houston (UTHealth Houston). Successes, challenges, and lessons learned are shared so that others planning or considering withdrawing may benefit from our experience. Conclusion: The resources provided for withdrawal within the eFSAP Form 1 Amendment Instructions are relatively basic, and additional details are not currently found in other FSAP guidance documents. Therefore, direct communication and support from the FSAP to the entity Responsible Officials are imperative to ensure a safe, secure, and compliant withdrawal.

Acceptability and Usability of the Family Gene Toolkit for Swiss and Korean Families Harboring BRCA1/BRAC2 Pathogenic Variants: A Web-Based Platform for Cascade Genetic Testing.

The study adapted the Family Gene Toolkit and developed a customized web application for Swiss and Korean families harboring BRCA1 or BRCA2 pathogenic variants to support family communication of genetic testing results and promote cascade genetic testing among at-risk relatives. In the first step, narrative data from 68 women with BRCA1/BRCA2 pathogenic variants and clinician feedback informed a culturally sensitive adaptation of the content consistent with current risk management guidelines. In the second step, the Information Technology team developed the functions and the interface of the web application that will host the intervention. In the third step, a new sample of 18 women from families harboring BRCA1/BRCA2 pathogenic variants tested the acceptability and usability of the intervention using "think-aloud" interviews and a questionnaire. Participants expressed high levels of satisfaction with the intervention. They provided positive feedback for the information regarding active coping, strategies to enhance family communication, interactive elements, and illustrative stories. They reported that the information was useful and the web application was easy to navigate. Findings suggest that the Family Gene Toolkit is well-designed and can increase rates of cascade testing among at-risk relatives. Its efficacy will be tested in a subsequent randomized trial.

Identifying and removing ableism from Tier 1 school-wide positive behaviour support practices.

Across Australia, almost one third of schools have been trained to implement school-wide positive behaviour support (SWPBS). As part of a Tier 1 approach, students are expected to demonstrate expected behaviours. By defining these behaviours in conjunction with students and families, and explicitly teaching these to students, schools implementing SWPBS can create climates where students can thrive both academically and behaviourally. However, many students with disability continue to be over-represented in discipline data in all schools, including those implementing SWPBS. We argue this is because defining the behaviours we want to see and celebrate is only part of the solution. Implementation is destined to fail if we do not, in tandem, address the conditions we created that act as barriers for students with disability. Further, through an analysis of Australian SWPBS matrices, we show that structural ableism exists in the way some expected behaviours are framed by requiring a greater response effort from students with disability if they are to meet the standard expected. We offer suggestions for schools to both recognise and remove ableism from Tier 1 SWPBS practices.

Universal Teacher-Child Interaction Training in early childhood special education: A cluster randomized control trial.

Growing evidence suggests that Teacher-Child Interaction Training-Universal (TCIT-U) is effective for increasing teachers' use of strategies that promote positive child behavior, but more rigorous research with larger, diverse samples is needed to understand the effects of TCIT-U on teacher and child outcomes in early childhood special education. Using a cluster randomized control trial, we evaluated the effects of TCIT-U on (a) teacher skill acquisition and self-efficacy and (b) child behavior and developmental functioning. Teachers in the TCIT-U group (n = 37) exhibited significantly greater increases in positive attention skills, increased consistent responding, and decreased critical statements relative to teachers in the waitlist control group (n = 36) at post and 1-month follow-up (d's range from 0.52 to 1.61). Teachers in the TCIT-U group also exhibited significantly fewer directive statements (d's range from 0.52 to 0.79) and greater increases in self-efficacy compared to waitlist teachers at post (d's range from 0.60 to 0.76). TCIT-U was also associated with short-term benefits for child behavior. Frequency (d = 0.41) and total number of behavior problems (d = 0.36) were significantly lower in the TCIT-U group than in the waitlist group at post (but not follow-up), with small-to-medium effects. The waitlist group, but not the TCIT-U group, demonstrated an increasing trend in number of problem behaviors over time. There were no significant between-group differences in developmental functioning. Current findings build support for the effectiveness of TCIT-U as universal prevention of behavior problems with an ethnically and racially diverse sample of teachers and children, including children with developmental disabilities. Implications for implementation of TCIT-U in the early childhood special education setting are discussed.

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.

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.

Incomplete Penetrance of Population-Based Genetic Screening Results in Electronic Health Record.

The clinical value of population-based genetic screening projects depends on the actions taken on the findings. The Healthy Nevada Project (HNP) is an all-comer genetic screening and research project based in northern Nevada. HNP participants with CDC Tier 1 findings of hereditary breast and ovarian cancer syndrome (HBOC), Lynch syndrome (LS), or familial hypercholesterolemia (FH) are notified and provided with genetic counseling. However, the HNP subsequently takes a "hands-off" approach: it is the responsibility of notified participants to share their findings with their healthcare providers, and providers are expected to implement the recommended action plans. Thus, the HNP presents an opportunity to evaluate the efficiency of participant and provider responses to notification of important genetic findings, using electronic health records (EHRs) at Renown Health (a large regional hospital in northern Nevada). Out of 520 HNP participants with findings, we identified 250 participants who were notified of their findings and who had an EHR. 107 of these participants responded to a survey, with 76 (71%) indicating that they had shared their findings with their healthcare providers. However, a sufficiently specific genetic diagnosis appeared in the EHRs and problem lists of only 22 and 10%, respectively, of participants without prior knowledge. Furthermore, review of participant EHRs provided evidence of possible relevant changes in clinical care for only a handful of participants. Up to 19% of participants would have benefited from earlier screening due to prior presentation of their condition. These results suggest that continuous support for both participants and their providers is necessary to maximize the benefit of population-based genetic screening. We recommend that genetic screening projects require participants' consent to directly document their genetic findings in their EHRs. Additionally, we recommend that they provide healthcare providers with ongoing training regarding documentation of findings and with clinical decision support regarding subsequent care.

From the patient to the population: Use of genomics for population screening.

Genomic medicine is expanding from a focus on diagnosis at the patient level to prevention at the population level given the ongoing under-ascertainment of high-risk and actionable genetic conditions using current strategies, particularly hereditary breast and ovarian cancer (HBOC), Lynch Syndrome (LS) and familial hypercholesterolemia (FH). The availability of large-scale next-generation sequencing strategies and preventive options for these conditions makes it increasingly feasible to screen pre-symptomatic individuals through public health-based approaches, rather than restricting testing to high-risk groups. This raises anew, and with urgency, questions about the limits of screening as well as the moral authority and capacity to screen for genetic conditions at a population level. We aimed to answer some of these critical questions by using the WHO Wilson and Jungner criteria to guide a synthesis of current evidence on population genomic screening for HBOC, LS, and FH.

The Impact of Proband Indication for Genetic Testing on the Uptake of Cascade Testing Among Relatives.

Although multiple factors can influence the uptake of cascade genetic testing, the impact of proband indication has not been studied. We performed a retrospective, cross-sectional study comparing cascade genetic testing rates among relatives of probands who received either diagnostic germline testing or non-indication-based proactive screening via next-generation sequencing (NGS)-based multigene panels for hereditary cancer syndromes (HCS) and/or familial hypercholesterolemia (FH). The proportion of probands with a medically actionable (positive) finding were calculated based on genes associated with Centers for Disease Control and Prevention (CDC) Tier 1 conditions, HCS genes, and FH genes. Among probands with a positive finding, cascade testing rates and influencing factors were assessed. A total of 270,715 probands were eligible for inclusion in the study (diagnostic n = 254,281,93.9%; proactive n = 16,434, 6.1%). A positive result in a gene associated with a CDC Tier 1 condition was identified in 10,520 diagnostic probands (4.1%) and 337 proactive probands (2.1%), leading to cascade testing among families of 3,305 diagnostic probands (31.4%) and 36 proactive probands (10.7%) (p < 0.0001). A positive result in an HCS gene was returned to 23,272 diagnostic probands (9.4%) and 970 proactive probands (6.1%), leading to cascade testing among families of 6,611 diagnostic probands (28.4%) and 89 proactive probands (9.2%) (p < 0.0001). Cascade testing due to a positive result in an HCS gene was more commonly pursued when the diagnostic proband was White, had a finding in a gene associated with a CDC Tier 1 condition, or had a personal history of cancer, or when the proactive proband was female. A positive result in an FH gene was returned to 1,647 diagnostic probands (25.3%) and 67 proactive probands (0.62%), leading to cascade testing among families of 360 diagnostic probands (21.9%) and 4 proactive probands (6.0%) (p < 0.01). Consistently higher rates of cascade testing among families of diagnostic probands may be due to a perceived urgency because of personal or family history of disease. Due to the proven clinical benefit of cascade testing, further research on obstacles to systematic implementation and uptake of testing for relatives of any proband with a medically actionable variant is warranted.

The Communication Chain of Genetic Risk: Analyses of Narrative Data Exploring Proband-Provider and Proband-Family Communication in Hereditary Breast and Ovarian Cancer.

Low uptake of genetic services among members of families with hereditary breast and ovarian cancer (HBOC) suggests limitations of proband-mediated communication of genetic risk. This study explored how genetic information proceeds from healthcare providers to probands and from probands to relatives, from the probands' perspectives. Using a grounded-theory approach, we analyzed narrative data collected with individual interviews and focus groups from a sample of 48 women identified as carriers of HBOC-associated pathogenic variants from three linguistic regions of Switzerland. The findings describe the "communication chain", confirming the difficulties of proband-mediated communication. Provider-proband communication is impacted by a three-level complexity in the way information about family communication is approached by providers, received by probands, and followed-up by the healthcare system. Probands' decisions regarding disclosure of genetic risk are governed by dynamic and often contradictory logics of action, interconnected with individual and family characteristics, eventually compelling probands to engage in an arbitrating process. The findings highlight the relevance of probands' involvement in the communication of genetic risk to relatives, suggesting the need to support them in navigating the complexity of family communication rather than replacing them in this process. Concrete actions at the clinical and health system levels are needed to improve proband-mediated communication.