Population screening for BRCA1/BRCA2 mutations: lessons from qualitative analysis of the screening experience

BRCA awareness and testing experience in the UK Jewish population: a qualitative study

BACKGROUND

1 in 40 UK Jewish individuals carry a pathogenic variant in BRCA1/BRCA2. Traditional testing criteria miss half of carriers, and so population genetic testing is being piloted for Jewish people in England. There has been no qualitative research into the factors influencing BRCA awareness and testing experience in this group. This study aimed to explore these and inform improvements for the implementation of population genetic testing.

METHODS

Qualitative study of UK Jewish adults who have undergone BRCA testing. We conducted one-to-one semistructured interviews via telephone or video call using a predefined topic guide, until sufficient information power was reached. Interviews were audio-recorded, transcribed verbatim and interpreted using applied thematic analysis.

RESULTS

32 individuals were interviewed (28 carriers, 4 non-carriers). We interpreted five themes intersecting across six time points of the testing pathway: (1) individual differences regarding personal/family history of cancer, demographics and personal attitudes/approach; (2) healthcare professionals' support; (3) pathway access and integration; (4) nature of family/partner relationships; and (5) Jewish community factors. Testing was largely triggered by connecting information to a personal/family history of cancer. No participants reported decision regret, although there was huge variation in satisfaction. Suggestions were given around increasing UK Jewish community awareness, making information and support services personally relevant and proactive case management of carriers.

CONCLUSIONS

There is a need to improve UK Jewish community BRCA awareness and to highlight personal relevance of testing for individuals without a personal/family history of cancer. Traditional testing criteria caused multiple issues regarding test access and experience. Carriers want information and support services tailored to their individual circumstances.

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.

Unselected Population Genetic Testing for Personalised Ovarian Cancer Risk Prediction: A Qualitative Study Using Semi-Structured Interviews

Unselected population-based personalised ovarian cancer (OC) risk assessments combining genetic, epidemiological and hormonal data have not previously been undertaken. We aimed to understand the attitudes, experiences and impact on the emotional well-being of women from the general population who underwent unselected population genetic testing (PGT) for personalised OC risk prediction and who received low-risk (<5% lifetime risk) results. This qualitative study was set within recruitment to a pilot PGT study using an OC risk tool and telephone helpline. OC-unaffected women ≥ 18 years and with no prior OC gene testing were ascertained through primary care in London. In-depth, semi-structured and 1:1 interviews were conducted until informational saturation was reached following nine interviews. Six interconnected themes emerged: health beliefs; decision making; factors influencing acceptability; effect on well-being; results communication; satisfaction. Satisfaction with testing was high and none expressed regret. All felt the telephone helpline was helpful and should remain optional. Delivery of low-risk results reduced anxiety. However, care must be taken to emphasise that low risk does not equal no risk. The main facilitators were ease of testing, learning about children’s risk and a desire to prevent disease. Barriers included change in family dynamics, insurance, stigmatisation and personality traits associated with stress/worry. PGT for personalised OC risk prediction in women in the general population had high acceptability/satisfaction and reduced anxiety in low-risk individuals. Facilitators/barriers observed were similar to those reported with genetic testing from high-risk cancer clinics and unselected PGT in the Jewish population.

Targeted BRCA1/2 population screening among Ashkenazi Jewish individuals using a web-enabled medical model: An observational cohort study

PURPOSE

This study aimed to evaluate uptake and follow-up using internet-assisted population genetic testing (GT) for BRCA1/2 Ashkenazi Jewish founder pathogenic variants (AJPVs).

METHODS

Across 4 cities in the United States, from December 2017 to March 2020, individuals aged ≥25 years with ≥1 Ashkenazi Jewish grandparent were offered enrollment. Participants consented and enrolled online with chatbot and video education, underwent BRCA1/2 AJPV GT, and chose to receive results from their primary care provider (PCP) or study staff. Surveys were conducted at baseline, at 12 weeks, and annually for 5 years.

RESULTS

A total of 5193 participants enrolled and 4109 (79.1%) were tested (median age = 54, female = 77.1%). Upon enrollment, 35.1% of participants selected a PCP to disclose results, and 40.5% of PCPs agreed. Of those tested, 138 (3.4%) were AJPV heterozygotes of whom 21 (15.2%) had no significant family history of cancer, whereas 86 (62.3%) had a known familial pathogenic variant. At 12 weeks, 85.5% of participants with AJPVs planned increased cancer screening; only 3.7% with negative results and a significant family history reported further testing.

CONCLUSION

Although continued follow-up is needed, internet-enabled outreach can expand access to targeted GT using a medical model. Observed challenges for population genetic screening efforts include recruitment barriers, improving PCP engagement, and increasing uptake of additional testing when indicated.

Adherence to NCCN Guidelines for Genetic Testing in Breast Cancer Patients: Who Are We Missing?

BACKGROUND

Genetic predisposition accounts for 5-10% of all breast cancers (BC) diagnosed. NCCN guidelines help providers identify appropriate candidates for counseling and testing. Concerns about underutilization of genetic testing have spurred interest in broader peri-diagnostic testing. We evaluated surgeon adherence to NCCN guidelines and studied patterns of testing in newly diagnosed BC patients.

METHODS

A total of 397 patients were identified with newly diagnosed BC treated at our institution between 2016 and 2017 with no prior genetic testing. Eligibility for genetic testing based on NCCN criteria, referral, and patient compliance were recorded.

RESULTS

In total, 212 of 397 (53%) met NCCN testing criteria. Fifty-nine of 212 (28%) patients went untested despite meeting one or more criteria. Fourteen of 59 (24%) of these were referred but did not comply. Most common criteria for meeting eligibility for testing both in the overall cohort and among missed patients were family history-based. Age > 45 years old and non-Ashkenazi Jewish descent were predictive of missed referral (p < 0.01). We identified pathogenic mutations in 16 of 153 (10%) patients who did undergo testing (11 (7%) BRCA1 or 2 and 5 (3%) with other predisposition gene mutations) or 16 of 397 (4%) among the overall group.

CONCLUSIONS

Our data highlight the underutilization of genetic testing. Even in the setting of a full-service breast center with readily available genetic counseling, there is a substantial miss rate for identifying eligible patients, related to assessment of family history, patient age, and ethnicity, as well as patient compliance. Broader peri-diagnostic testing should be considered, and higher compliance rates with patients referred should be sought.

Population Screening for Inherited Predisposition to Breast and Ovarian Cancer

The discovery of genes underlying inherited predisposition to breast and ovarian cancer has revolutionized the ability to identify women at high risk for these diseases before they become affected. Women who are carriers of deleterious variants in these genes can undertake surveillance and prevention measures that have been shown to reduce morbidity and mortality. However, under current strategies, the vast majority of women carriers remain undetected until they become affected. In this review, we show that universal testing, particularly of the BRCA1 and BRCA2 genes, fulfills classical disease screening criteria. This is especially true for BRCA1 and BRCA2 in Ashkenazi Jews but is translatable to all populations and may include additional genes. Utilizing genetic information for large-scale precision prevention requires a paradigmatic shift in health-care delivery. To address this need, we propose a direct-to-patient model, which is increasingly pertinent for fulfilling the promise of utilizing personal genomic information for disease prevention.

Online BRCA1/2 screening in the Australian Jewish community: a qualitative study

Screening programmes for BRCA1/2 Jewish Founder mutations (JFM) in the Jewish community have been advocated internationally. Implementation of these programmes could decrease morbidity and mortality of BRCA1/2 JFM carriers through the uptake of cancer screening strategies and risk-reducing surgery. An online programme offered to the Sydney Jewish community that delivers pre-test information and collects consent for BRCA1/2 JFM testing via a website is currently being evaluated (JeneScreen). Forty-three participants from JeneScreen were invited to participate in a sub-study, of semi-structured pre- and post-result telephone interviews. Eleven participants consented to the sub-study. The interviews explored their experiences regarding the online model of obtaining pre-test genetic information, giving consent and receiving results. Inductive thematic analysis was carried out on the interviews. Overarching themes identified include (1) embracing online testing, (2) the online pre-test experience, (3) the result notification experience, (4) concerns associated with online testing and (5) testing as a responsibility. Overall, participants were highly satisfied with online BRCA1/2 JFM testing, an indication that the a website for pre-test information provision is an acceptable alternative to in-person genetic counselling for BRCA1/2 JFM screening and represents a feasible model for future community screening efforts.

How can Australia integrate routine genetic sequencing in oncology: a qualitative study through an implementation science lens

PURPOSE

This study sought to determine genetics and oncology specialists' views of integrating BRCA1 and BRCA2 testing in epithelial ovarian and breast cancer into routine practice.

METHODS

Qualitative interviews were designed using the Consolidated Framework for Implementation Research. Questions included experiences or views of the BRCA testing processes, implementation needs of oncology health professionals, perceived challenges, and future ideas for interventions to integrate genetic testing into oncology.

RESULTS

Twenty-two participants were interviewed from twelve health organizations and four themes were identified: (1) embracing the shift to mainstream genetic testing, with the majority of participants viewing BRCA testing as clinically useful and routine use important for maintaining a patient centered process; (2) the need for communication networks and role delineation to integrate routine genetic testing; (3) factors that influence sustaining routine genetic testing, including ongoing training, resources and funding, real-world adaptation, system complexity, and champions; and (4) variation in system interventions for integrating routine genetic testing align to organizational context.

CONCLUSION

Findings illustrate the need for integrating genetic testing into routine oncology, and that adaptation of interventions and processes is essential to sustain a feasible model. An understanding of individual and organizational implementation factors will help to prepare for future integration of routine genetic testing in other cancers.

Population-based Genetic Testing for Precision Prevention

Global interest in genetic testing for cancer susceptibility genes (CSG) has surged with falling costs, increasing awareness, and celebrity endorsement. Current access to genetic testing is based on clinical criteria/risk model assessment which uses family history as a surrogate. However, this approach is fraught with inequality, massive underutilization, and misses 50% CSG carriers. This reflects huge missed opportunities for precision prevention. Early CSG identification enables uptake of risk-reducing strategies in unaffected individuals to reduce cancer risk. Population-based genetic testing (PGT) can overcome limitations of clinical criteria/family history-based testing. Jewish population studies show population-based BRCA testing is feasible, acceptable, has high satisfaction, does not harm psychologic well-being/quality of life, and is extremely cost-effective, arguing for changing paradigm to PGT in the Jewish population. Innovative approaches for delivering pretest information/education are needed to facilitate informed decision-making for PGT. Different health systems will need context-specific implementation strategies and management pathways, while maintaining principles of population screening. Data on general population PGT are beginning to emerge, prompting evaluation of wider implementation. Sophisticated risk prediction models incorporating genetic and nongenetic data are being used to stratify populations for ovarian cancer and breast cancer risk and risk-adapted screening/prevention. PGT is potentially cost-effective for panel testing of breast and ovarian CSGs and for risk-adapted breast cancer screening. Further research/implementation studies evaluating the impact, clinical efficacy, psychologic and socio-ethical consequences, and cost-effectiveness of PGT are needed.

Assessing the implications of positive genomic screening results

Aim:

Before population screening of ‘healthy’ individuals is widely adopted, it is important to consider the harms and benefits of receiving positive results and how harms and benefits may differ by age.

Subjects & methods:

Participants in a preventive genomic screening study were screened for 17 genes associated with 11 conditions. We interviewed 11 participants who received positive results.

Results:

Interviewees expressed little concern about their positive results in light of their older age, the risk condition for which they tested positive, or other pressing health concerns.

Conclusion:

Researchers and clinicians should recognize that returning positive results may not have the impact they presume given the diversity of the conditions screened and those who choose to undergo screening.

Population-based genetic testing for Women's cancer prevention

Germline mutations in cancer-susceptibility-genes (CSG) can dramatically increase womens' lifetime risk of ovarian, endometrial, breast and bowel cancers. Identification of unaffected carriers is important to enable proactive engagement with highly effective screening and preventive options to minimise cancer risk. Currently, a family-history model is used to identify individuals with CSGs. Complex regional referral guidelines specify the family-history criteria required before an individual is eligible for genetic-testing. This model is ineffective, resource intense, misses >50% CSG carriers, is associated with underutilisation of genetic-testing services and delays detection of mutation carriers. Although awareness and detection of CSG-carriers has improved, over 97% carriers remain unidentified. This reflects significant missed opportunities for precision-prevention. Population-based genetic-testing (PBGT) represents a novel healthcare strategy with the potential to dramatically improve detection of unaffected CSG-carriers along with enabling population risk-stratification for cancer precision-prevention. Several research studies have assessed the impact, feasibility, acceptability, long-term psychological outcomes and cost-effectiveness of population-based BRCA-testing in the Ashkenazi-Jewish population. Initial data on PBGT in the general-population is beginning to emerge and large implementation studies investigating PBGT in the general-population are needed. This review will summarise the current research into the clinical, psycho-social, health-economic, societal and ethical consequences of a PBGT model for women's cancer precision-prevention.

Multi-Gene Panel Testing of 23,179 Individuals for Hereditary Cancer Risk Identifies Pathogenic Variant Carriers Missed by Current Genetic Testing Guidelines

Recent advancements in next-generation sequencing have greatly expanded the use of multi-gene panel testing for hereditary cancer risk. Although genetic testing helps guide clinical diagnosis and management, testing recommendations are based on personal and family history of cancer and ethnicity, and many carriers are being missed. Herein, we report the results from 23,179 individuals who were referred for 30-gene next-generation sequencing panel testing for hereditary cancer risk, independent of current testing guidelines-38.7% of individuals would not have met National Comprehensive Cancer Network criteria for genetic testing. We identified a total of 2811 pathogenic variants in 2698 individuals for an overall pathogenic frequency of 11.6% (9.1%, excluding common low-penetrance alleles). Among individuals of Ashkenazi Jewish descent, three-quarters of pathogenic variants were outside of the three common BRCA1 and BRCA2 founder alleles. Across all ethnic groups, pathogenic variants in BRCA1 and BRCA2 occurred most frequently, but the contribution of pathogenic variants in other genes on the panel varied. Finally, we found that 21.7% of individuals with pathogenic variants in genes with well-established genetic testing recommendations did not meet corresponding National Comprehensive Cancer Network criteria. Taken together, the results indicate that more individuals are at genetic risk for hereditary cancer than are identified by current testing guidelines and/or use of single-gene or single-site testing.

Attitude towards and factors affecting uptake of population-based BRCA testing in the Ashkenazi Jewish population: a cohort study

OBJECTIVE

To evaluate factors affecting unselected population-based BRCA testing in Ashkenazi Jews (AJ).

DESIGN

Cohort-study set within recruitment to the GCaPPS trial (ISRCTN73338115).

SETTING

North London AJ population.

POPULATION OR SAMPLE

Ashkenazi Jews women/men >18 years, recruited through self-referral.

METHODS

Ashkenazi Jews women/men underwent pre-test counselling for BRCA testing through recruitment clinics (clusters). Consenting individuals provided blood samples for BRCA testing. Data were collected on socio-demographic/family history/knowledge/psychological well-being along with benefits/risks/cultural influences (18-item questionnaire measuring 'attitude'). Four-item Likert-scales analysed initial 'interest' and 'intention-to-test' pre-counselling. Uni- and multivariable logistic regression models evaluated factors affecting uptake/interest/intention to undergo BRCA testing. Statistical inference was based on cluster robust standard errors and joint Wald tests for significance. Item-Response Theory and graded-response models modelled responses to 18-item questionnaire.

MAIN OUTCOME MEASURES

Interest, intention, uptake, attitude towards BRCA testing.

RESULTS

A total of 935 individuals (women = 67%/men = 33%; mean age = 53.8 (SD = 15.02) years) underwent pre-test genetic-counselling. During the pre-counselling, 96% expressed interest in and 60% indicated a clear intention to undergo BRCA testing. Subsequently, 88% opted for BRCA testing. BRCA-related knowledge (P = 0.013) and degree-level education (P = 0.01) were positively and negatively (respectively) associated with intention-to-test. Being married/cohabiting had four-fold higher odds for BRCA testing uptake (P = 0.009). Perceived benefits were associated with higher pre-counselling odds for interest in and intention to undergo BRCA testing. Reduced uncertainty/reassurance were the most important factors contributing to decision-making. Increased importance/concern towards risks/limitations (confidentiality/insurance/emotional impact/inability to prevent cancer/marriage ability/ethnic focus/stigmatisation) were significantly associated with lower odds of uptake of BRCA testing, and discriminated between acceptors and decliners. Male gender/degree-level education (P = 0.001) had weaker correlations, whereas having children showed stronger (P = 0.005) associations with attitudes towards BRCA testing.

CONCLUSIONS

BRCA testing in the AJ population has high acceptability. Pre-test counselling increases awareness of disadvantages/limitations of BRCA testing, influencing final cost-benefit perception and decision-making on undergoing testing.

TWEETABLE ABSTRACT

BRCA testing in Ashkenazi Jews has high acceptability and uptake. Pre-test counselling facilitates informed decision-making.

A Pragmatic Testing-Eligibility Framework for Population Mutation Screening: The Example of BRCA1/2

BACKGROUND

Eligibility guidelines for genetic testing may be revisited, given technological advances, plummeting costs, and proposals for population mutation screening. A key property of eligibility criteria is the tradeoff between the number of mutation carriers identified versus population members tested. We assess the fractions of mutation carriers identified, versus women undergoing mutation testing, for BRCA1/2 founder mutation screening in U.S. Ashkenazi-Jewish women.

METHODS

BRCA1/2 carrier probabilities, based on personal/family history, were calculated using the risk-prediction tool BRCAPRO for 4,589 volunteers (102 mutation carriers) in the population-based Washington Ashkenazi Study. For each carrier-probability threshold between 0% and 10%, we compared the percentage of founder mutations detected versus the percentage of women requiring mutation testing. PCR mutation testing was conducted at the NIH for the 3 Ashkenazi-Jewish founder mutations (5382insC and 185delAG in BRCA1, and 6174delT in BRCA2).

RESULTS

Identifying 90% of BRCA1/2 founder mutations required testing the 60% of Ashkenazi-Jewish women with carrier probabilities exceeding 0.56%, potentially avoiding mutation testing for approximately 0.7 to 1.1 million U.S. Ashkenazi-Jewish women. Alternatively, testing the 44% whose carrier probability exceeded 0.78% identified 80% of mutation carriers, increasing to 89% of mutation carriers when accounting for cascade testing triggered after mutation-positive daughters were identified by screening. We present data on all carrier-probability thresholds, e.g., a 5% threshold identified 46% of mutation carriers while testing 10% of women.

CONCLUSIONS

Different carrier-probability thresholds offered diverse tradeoffs between numbers of identified mutation carriers versus women tested. Low carrier-probability thresholds identified 90% of BRCA1/2 founder mutation carriers, without testing approximately 1 million U.S. Ashkenazi-Jewish women with lowest carrier probabilities.

IMPACT

In general, this risk-based framework could provide useful new options to consider during eligibility-criteria development for population mutation screening.

Next-Generation Service Delivery: A Scoping Review of Patient Outcomes Associated with Alternative Models of Genetic Counseling and Genetic Testing for Hereditary Cancer

The combination of increased referral for genetic testing and the current shortage of genetic counselors has necessitated the development and implementation of alternative models of genetic counseling and testing for hereditary cancer assessment. The purpose of this scoping review is to provide an overview of the patient outcomes that are associated with alternative models of genetic testing and genetic counseling for hereditary cancer, including germline-only and tumor testing models. Seven databases were searched, selecting studies that were: (1) full-text articles published ≥2007 or conference abstracts published ≥2015, and (2) assessing patient outcomes of an alternative model of genetic counseling or testing. A total of 79 publications were included for review and synthesis. Data-charting was completed using a data-charting form that was developed by the study team for this review. Seven alternative models were identified, including four models that involved a genetic counselor: telephone, telegenic, group, and embedded genetic counseling models; and three models that did not: mainstreaming, direct, and tumor-first genetic testing models. Overall, these models may be an acceptable alternative to traditional models on knowledge, patient satisfaction, psychosocial measures, and the uptake of genetic testing; however, particular populations may be better served by traditional in-person genetic counseling. As precision medicine initiatives continue to advance, institutions should consider the implementation of new models of genetic service delivery, utilizing a model that will best serve the needs of their unique patient populations.

Population Based Testing for Primary Prevention: A Systematic Review

The current clinical model for genetic testing is based on clinical-criteria/family-history (FH) and a pre-defined mutation probability threshold. It requires people to develop cancer before identifying unaffected individuals in the family to target prevention. This process is inefficient, resource intensive and misses >50% of individuals or mutation carriers at risk. Population genetic-testing can overcome these limitations. It is technically feasible to test populations on a large scale; genetic-testing costs are falling and acceptability and awareness are rising. MEDLINE, EMBASE, Pubmed, CINAHL and PsychINFO databases were searched using free-text and MeSH terms; retrieved reference lists of publications were screened; additionally, web-based platforms, Google, and clinical-trial registries were searched. Quality of studies was evaluated using appropriate check-lists. A number of studies have evaluated population-based BRCA-testing in the Jewish population. This has been found to be acceptable, feasible, clinically-effective, safe, associated with high satisfaction rates and extremely cost-effective. Data support change in guidelines for population-based BRCA-testing in the Jewish population. Population panel testing for BRCA1/BRCA2/RAD51C/RAD51D/BRIP1/PALB2 gene mutations is the most cost-effective genetic-testing strategy in general-population women and can prevent thousands more breast and ovarian cancers than current clinical-criteria based approaches. A few ongoing studies are evaluating population-based genetic-testing for multiple cancer susceptibility genes in the general population but more implementation studies are needed. A future population-testing programme could also target other chronic diseases.

Developing a conceptual, reproducible, rubric-based approach to consent and result disclosure for genetic testing by clinicians with minimal genetics background

Purpose

In response to genetic testing being widely ordered by non-genetics clinicians, the Consent and Disclosure Recommendations (CADRe) Workgroup of the Clinical Genome Resource (ClinGen; clinicalgenome.org) developed guidance to facilitate communication about genetic testing and efficiently improve the patient experience. Considering ethical, legal, social implications and medical factors, CADRe developed and pilot tested two rubrics addressing consent for genetic testing and results disclosure. The CADRe rubrics allow for adjusting the communication approach based on circumstances specific to patients and ordering clinicians.

Methods

We present results of a formative survey of 66 genetics clinicians to assess the consent rubric for 9 genes (MLH1, CDH1, TP53, GJB2, OTC; DMD, HTT, and CYP2C9/VKORC1). We also conducted interviews and focus groups with family and patient stakeholders (N=18), non-genetics specialists (N=27) and genetics clinicians (N=32) on both rubrics.

Results

Formative evaluation of the CADRe rubrics suggests key factors on which to make decisions about consent and disclosure discussions for a ‘typical’ patient.

Conclusion

We propose that the CADRe rubrics include the primary issues necessary to guide communication recommendations, and are ready for pilot testing by non-genetics clinicians. Consultation with genetics clinicians can be targeted towards more complex or intensive consent and disclosure counseling.

Military genomics: a perspective on the successes and challenges of genomic medicine in the Armed Services

We describe the impact genomics has on the health and readiness of the military service member, highlight several examples of the current and future plans for genomic medicine within the military, discuss challenges to implementation and provide recommendations to address some of those challenges.

Assessing risk for Mendelian disorders in a Bronx population

Background

To identify variants likely responsible for Mendelian disorders among the three major ethnic groups in the Bronx that might be useful to include in genetic screening panels or whole exome sequencing filters and to estimate their likely prevalence in these populations.

Methods

Variants from a high‐density oligonucleotide screen of 192 members from each of the three ethnic‐national populations (African Americans, Puerto Ricans, and Dominicans) were evaluated for overlap with next generation sequencing data. Variants were curated manually for clinical validity and utility using the American College of Medical Genetics (ACMG) scoring system. Additional variants were identified through literature review.

Results

A panel of 75 variants displaying autosomal dominant, autosomal recessive, autosomal recessive/digenic recessive, X‐linked recessive, and X‐linked dominant inheritance patterns representing 39 Mendelian disorders were identified among these populations.

Conclusion

Screening for a broader range of disorders could offer the benefits of early or presymptomatic diagnosis and reproductive choice.