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Genome sequencing (GS) outperforms other rare disease diagnostics, but standardized approaches to assessing its clinical utility are limited. This study assessed the validity of the Clinician-reported Genetic testing Utility InDEx (C-GUIDE), a novel tool for assessing the utility of genetic testing from a clinician's perspective, for GS. C-GUIDE ratings were completed for patients who received GS results. For each patient, total C-GUIDE and single item global scores were calculated. Construct validity was assessed using linear regression to determine the association between C-GUIDE total and global item scores and measure the effects of potential explanatory variables. Ratings were completed for 67 pediatric and 36 adult patients. GS indications were neurological for 70.9% and results were diagnostic for 28.2%. When the C-GUIDE assessed primary (PV), secondary (SV), and pharmacogenomic (PGx) variants, on average, a one unit increase in the global item score was associated with an increase of 7.3 in the C-GUIDE score (p < 0.05). Diagnostic results were associated with an increase in C-GUIDE score of 5.0 compared to non-diagnostic results (p < 0.05) and an increase of one SV was associated with an increase of 2.5 (p < 0.05). For children, decreased age of one year was associated with an increase in C-GUIDE score of 0.3 (p < 0.05). Findings provide evidence that C-GUIDE measures the construct of clinical utility in pediatric and adult rare disease populations and is sensitive to changes in utility related to variant type. Quantifying the clinical utility of GS using C-GUIDE can inform efforts to optimize its use in patient care., (© 2022. The Author(s).)

Cascade genetic testing is the identification of individuals at risk for a hereditary condition by genetic testing in relatives of people known to possess particular genetic variants. Cascade testing has health system implications, however cascade costs and health effects are not considered in health technology assessments (HTAs) that focus on costs and health consequences in individual patients. Cascade health service use must be better understood to be incorporated in HTA of emerging genetic tests for children. The purpose of this review was to characterise published research related to patterns and costs of cascade health service use by relatives of children with any condition diagnosed through genetic testing. To this end, a scoping literature review was conducted. Citation databases were searched for English-language papers reporting uptake, costs, downstream health service use, or cost-effectiveness of cascade investigations of relatives of children who receive a genetic diagnosis. Included publications were critically appraised, and findings were synthesised. Twenty publications were included. Sixteen had a paediatric proband population; four had a combined paediatric and adult proband population. Uptake of cascade testing varied across diseases, from 37% for cystic fibrosis, 39% to 65% for hypertrophic cardiomyopathy, and 90% for rare monogenic conditions. Two studies evaluated costs. It was concluded that cascade testing in the child-to-parent direction has been reported in a variety of diseases, and that understanding the scope of cascade testing will aid in the design and conduct of HTA of emerging genetic technologies to better inform funding and policy decisions., (© 2021. The Author(s).)

Standardized approaches to measuring clinical utility will enable more robust evaluations of genetic tests. To characterize how clinical utility has been measured, this scoping review examined outcomes used to operationalize this concept in the context of genetic testing, spanning relevant literature (2015-2017). The search strategy and analysis were guided by the Fryback and Thornbury hierarchical model of efficacy (FT Model). Through searches in Ovid MEDLINE, EMBASE and Web of Science, 194 publications were identified for inclusion. Two coders reviewed titles, abstracts, and full texts to determine eligibility. Results were analyzed using thematic and frequency analyses. This review generated a catalog of outcomes mapped to the efficacy domains of the FT Model. The degree of representation observed in each domain varied by the clinical purpose and clinical indication of genetic testing. Diagnostic accuracy (68%), technical (28.4%), and patient outcome (28.4%) efficacy studies were represented at the highest rate. Findings suggest that the FT Model is suitable for the genetics context however domain refinements may be warranted. More diverse clinical settings, robust study designs, and novel strategies for measuring clinical utility are needed.

The clinical use of whole-genome sequencing (WGS) is expected to alter pediatric medical management. The study aimed to describe the type and cost of healthcare activities following pediatric WGS compared to chromosome microarray (CMA). Healthcare activities prompted by WGS and CMA were ascertained for 101 children with developmental delay over 1 year. Activities following receipt of non-diagnostic CMA were compared to WGS diagnostic and non-diagnostic results. Activities were costed in 2016 Canadian dollars (CDN). Ongoing care accounted for 88.6% of post-test activities. The mean number of lab tests was greater following CMA than WGS (0.55 vs. 0.09; p = 0.007). The mean number of specialist visits was greater following WGS than CMA (0.41 vs. 0; p = 0.016). WGS results (diagnostic vs. non-diagnostic) modified the effect of test type on mean number of activities (p < 0.001). The cost of activities prompted by diagnostic WGS exceeded $557CDN for 10% of cases. In complex pediatric care, CMA prompted additional diagnostic investigations while WGS prompted tailored care guided by genotypic variants. Costs for prompted activities were low for the majority and constitute a small proportion of total test costs. Optimal use of WGS depends on robust evaluation of downstream care and cost consequences.

Interpretation of pediatric chromosome microarray (CMA) results presents diagnostic and medical management challenges. Understanding management practices triggered by CMA will inform clinical utility and resource planning. Using a retrospective cohort design, we extracted clinical and management-related data from the records of 752 children with congenital anomalies and/or developmental delay who underwent CMA in an academic pediatric genetics clinic (2009-2011). Frequency distributions and relative rates (RR) of post-CMA medical recommendations in children with reportable and benign CMA results were calculated. Medical recommendations were provided for 79.6% of children with reportable results and 62.0% of children with benign results. Overall, recommendations included specialist consultation (40.8%), imaging (32.5%), laboratory investigations (17.2%), surveillance (4.6%), and family investigations (4.9%). Clinically significant variants and variants of uncertain clinical significance were associated with higher and slightly higher rates of management recommendations, respectively, compared with benign/no variants (RR=1.34; 95% CI (1.22-1.47); RR=1.23; 95% CI (1.09-1.38)). Recommendation rates for clinically significant versus uncertain results depended upon how uncertainty was classified (RRbroad=1.09; 95% CI (0.99-1.2); RRnarrow=1.12; 95% CI (1.02-1.24)). Recommendation rates also varied by the child's age and provider type. In conclusion, medical recommendations follow CMA for the majority of children. Compared with benign CMA results, clinically significant CMA variants are a significant driver of pediatric medical recommendations. Variants of uncertain clinical significance drive recommendations, but to a lesser extent. As a broadening range of specialists will need to respond to CMA results, targeted capacity building is warranted.

Growing discussion on the use of whole-genome or exome sequencing (WG/ES) in newborn screening (NBS) has raised concerns regarding the generation of incidental information on millions of infants annually. It is unknown whether integrating WG/ES would alter public expectations regarding participation in universal NBS. We assessed public willingness to participate in NBS using WG/ES compared with current NBS. Our secondary objective was to assess the public's beliefs regarding a parental responsibility to participate in WG/ES-based NBS compared with current NBS. We examined self-reported attitudes regarding willingness to participate in NBS using a cross-sectional national survey of Canadian residents recruited through an internet panel, reflective of the Canadian population by age, gender and region. Our results showed that fewer respondents would be willing to participate in NBS using WG/ES compared with NBS using current technologies (80 vs 94%, P<0.001), or perceived a parental responsibility to participate in WG/ES-based NBS vs current NBS (30 vs 48%, P<0.001). Our findings suggest that integrating WG/ES into NBS might reduce participation, and challenge the moral authority that NBS programmes rely upon to ensure population benefits. These findings point to the need for caution in the untargeted use of WG/ES in public health contexts.

Developments in genomics, including next-generation sequencing technologies, are expected to enable a more personalized approach to clinical care, with improved risk stratification and treatment selection. In oncology, personalized medicine is particularly advanced and increasingly used to identify oncogenic variants in tumor tissue that predict responsiveness to specific drugs. Yet, the translational research needed to validate these technologies will be conducted in patients with late-stage cancer and is expected to produce results of variable clinical significance and incidentally identify genetic risks. To explore the experiential context in which much of personalized cancer care will be developed and evaluated, we conducted a qualitative interview study alongside a pilot feasibility study of targeted DNA sequencing of metastatic tumor biopsies in adult patients with advanced solid malignancies. We recruited 29/73 patients and 14/17 physicians; transcripts from semi-structured interviews were analyzed for thematic patterns using an interpretive descriptive approach. Patient hopes of benefit from research participation were enhanced by the promise of novel and targeted treatment but challenged by non-findings or by limited access to relevant trials. Family obligations informed a willingness to receive genetic information, which was perceived as burdensome given disease stage or as inconsequential given faced challenges. Physicians were optimistic about long-term potential but conservative about immediate benefits and mindful of elevated patient expectations; consent and counseling processes were expected to mitigate challenges from incidental findings. These findings suggest the need for information and decision tools to support physicians in communicating realistic prospects of benefit, and for cautious approaches to the generation of incidental genetic information.

Newborn screening (NBS) programs aim to identify affected infants before the onset of treatable disorders. Historically, benefits to the family and society were considered secondary to this clinical benefit; yet, recent discourse defending expanded NBS has argued that screening can in part be justified by secondary benefits, such as learning reproductive risk information to support family planning ('reproductive benefit'). Despite increased attention to these secondary benefits of NBS, stakeholders' values remain unknown. We report a mixed methods study that included an examination of providers' views toward the pursuit of reproductive risk information through NBS, using sickle cell disorder carrier status as an example. We surveyed a stratified random sample of 1615 providers in Ontario, and interviewed 42 providers across 7 disciplines. A majority endorsed the identification of reproductive risks as a goal of NBS (74-77%). Providers' dominant rationale was that knowledge of carrier status is an important and inherent benefit of NBS as it allows people to make reproductive choices, which is consistent with the goals of disease prevention. However, some challenged its appropriateness, questioning its logic, timing and impact on disease prevention. Others were sensitive to intruding on individuals' choices or children's independent rights. While the dominant view is consistent with discourse defending expanded NBS, it deviates from the traditional screening principles that underpin most public health interventions. Broader discussion of the balance between benefits to screened individuals and those to families and societies, in the context of public health programs, is needed.

The expansion of newborn screening (NBS) has been accompanied by debate about what benefits should be achieved and the role of parental discretion in their pursuit. The opportunity to inform parents of reproductive risks is among the most valued additional benefits gained through NBS, and assumes prominence where the primary goal of identifying a treatable condition is not assured. We reviewed 53 unique guidelines addressing prenatal, preconception and newborn screening to examine: (1) how generating reproductive risk information is construed as a benefit of screening; and (2) what conditions support the realization of this benefit. Most preconception and prenatal guidelines - where generating reproductive risk information is described as a primary benefit - required that individuals be given a 'cascade of choices', ensuring that each step in the decision-making process was well informed, from deciding to pursue information about reproductive risks to deciding how to manage them. With the exception of three guidelines, NBS policy infrequently attended to the potential for reproductive benefits; further, most guidelines that acknowledged such benefits construed voluntarism narrowly, without attention to the choices attendant on receiving reproductive risk information. This review suggests that prenatal and preconception guidance identifies a coherent framework to support the pursuit of reproductive benefits through population screening programmes. Interestingly, attention to reproductive benefits is increasing among NBS guidance, yet reflection on how such benefits ought to be pursued remains limited. Traditional norms for NBS may require reconsideration where the remit of screening exceeds the primary goal of clinical benefits for infants.

The expansion of newborn screening (NBS) is increasing the generation of incidental results, notably carrier results. Although carrier status is generally understood to be clinically benign, concerns persist that parents may misunderstand its meaning, with deleterious effects on children and their families. Expansion of the NBS panel in Ontario, Canada in 2006 to include sickle cell disorders drew attention to the policy challenge of incidental carrier results. We conducted a study of consumer and provider attitudes to inform policy on disclosure. In this paper, we report the results of (i) qualitative interviews with health-care providers, advocates and parents of carrier infants and (ii) focus groups with new parents and individuals active with the sickle cell community. Lay and provider participants generally believed that carrier results were clinically insignificant. However, some uncertainty persisted among lay consumers in the form of conjecture or doubt. In addition, consumers and advocates who were most informed about the disease articulated insistent yet dissonant claims of clinical significance. Meanwhile, providers referenced research knowledge to offer an equivocal assessment of the possibility and significance of clinically symptomatic carrier status. We conclude that many interpretations of carrier status are in circulation, failing to fit neatly into the categories of 'clinically significant' or 'benign.' This creates challenges for communicating clearly with parents - challenges exacerbated by inconsistent messages from screening programs regarding the significance of sickle cell carrier status. Disclosure policy related to incidentally generated infant carrier results needs to account for these complex realities.