Cascade screening for beta-thalassemia in Pakistan: development, feasibility and acceptability of a decision support intervention for relatives.

The government-funded 'Punjab Thalassaemia Prevention Project' (PTPP) in Pakistan includes cascade screening for biological relatives of children with beta-Thalassaemia Major (ß-TM). However, there is low uptake of cascade screening. This paper presents the (i) development of a paper-based 'decision support intervention for relatives' (DeSIRe) to enable PTPP Field Officers to facilitate informed decision making about carrier testing, and (ii) assessment of the feasibility and acceptability of the DeSIRe. The intervention was developed using the International Patient Decision Aids Standards quality criteria and Ottawa Decision Support Framework. Twelve focus groups were conducted (September and October 2020) to explore the views of healthcare professionals (HCPs) and relatives of children with ß-TM, in six cities. The focus groups were attended by 117 participants (60 HCPs and 57 relatives). Thematic analysis showed that the DeSIRe was considered acceptable for supporting relatives to make informed decisions about cascade screening, and potentially feasible for use in clinical practice. Suggestions for changing some words, the structure and adding information about how carrier testing relates to consanguineous marriages will enable further development of the DeSIRe. Participants generally welcomed the DeSIRe; however, they highlighted the perceived need to use more directive language, hence showed a cultural preference for directive genetic counselling. The findings highlight challenges for researchers using western theories, frameworks, policies and clinical guidelines to develop decision support interventions for implementation more globally. Future research is needed to evaluate the use of the DeSIRe in routine practice and whether it enables relatives to make informed decisions.

Exome-based preconception carrier testing for consanguineous couples in China.

OBJECTIVE: To evaluate the utility of clinical exome sequencing (ES)-based carrier screening in Chinese consanguineous couples. METHODS: Consanguineous couples were screened for autosomal recessive (AR) disorders using the clinical ES of 5000 genes associated with human diseases. RESULTS: We recruited 14 couples who elected to have sequencing. One couple was related as first cousins and 13 as second cousins. Both partners carrying the same pathogenic variant were detected in four couples. One couple was found in which one partner carried a splice variant, and the other had a missence variant of the same gene. These five couples were identified as being at risk of having a child affected by an AR disorder. CONCLUSION: Our study demonstrates that ES-based preconception screening yields a clinical value for Chinese consanguineous couples. It enables to detect at-risk couples for rare AR diseases.

Counseling for personal health implications identified during reproductive genetic carrier screening.

OBJECTIVE: Preconception and prenatal carrier screening is designed to provide reproductive risk information, but carriers for some autosomal recessive or X-linked conditions also have personal health risks. This study investigated the prevalence of and inclusion of personal health implications in pre- and post-test counseling. METHODS: Twelve genetic conditions with personal health risks for carriers included on carrier screening panels but not otherwise screened routinely were identified (e.g., Gaucher disease with Parkinson's disease risk). A retrospective review was performed of patients with a positive carrier screen for one of these conditions at our center from 2012 to 2019. RESULTS: Of 6147 individuals that had carrier screening for one of the twelve conditions, 96 (1.56%) did not report a known family history and screened positive for one of the conditions. Testing was ordered largely by reproductive endocrinologists (51.0%) and genetic counselors (35.4%). Most individuals did not receive pre- (96.8%) or post-test (64.6%) counseling about personal health risks. Post-test counseling was performed principally by genetic counselors (97.1%). For carriers of conditions with guidelines for specialist referral, most individuals (75.9%) were referred. CONCLUSION: Expanded genetic carrier screening increasingly identifies individuals with personal health implications, but patients are frequently not counseled before or after testing. These findings stress the importance of developing guidelines for practitioners about expanded carrier screening counseling and follow-up.

The cost-effectiveness of genotyping versus sequencing for prenatal cystic fibrosis carrier screening.

OBJECTIVE: We investigated the cost-effectiveness of three sequential prenatal cystic fibrosis (CF) carrier screening strategies: genotyping both partners, genotyping one partner then sequencing the second, and sequencing both partners. METHOD: A decision-analytic model compared the strategies in a theoretical cohort of four million pregnant couples in the US population and five racial/ethnic sub-populations. Inputs were obtained from literature and varied in sensitivity analysis. Outcomes included cost per quality-adjusted life year (QALY), missed carrier couples, affected newborns, missed prenatal diagnoses, terminations, and procedure-related losses. The cost-effectiveness threshold was $100,000/QALY. RESULTS: Sequencing both partners identified 1099 carrier couples that were missed by genotyping both partners, leading to 273 fewer missed prenatal diagnoses, 152 more terminations, and 152 fewer affected newborns. A similar trend was observed in the genotyping followed by sequencing strategy. The incremental cost-effectiveness ratio of genotyping followed by sequencing compared to genotyping both partners was $180,004/QALY and the incremental cost-effectiveness ratio of sequencing both partners compared to genotyping followed by sequencing was $17.6 million/QALY. Sequencing both partners was cost-effective below $339 per test, genotyping/sequencing between $340 and $1837, and genotyping both partners above $1838. Sequencing was not cost-effective among five racial/ethnic sub-populations. CONCLUSION: Despite improved outcomes, sequencing for prenatal CF carrier screening was not cost-effective compared to genotyping. The clinical significance of the incremental cost-effectiveness of CF carrier screening is a matter of deliberation for public policy debate.

Recommendation of premarital genetic screening in the Syrian Jewish community based on mutation carrier frequencies within Syrian Jewish cohorts.

BACKGROUND: There is a paucity of information available regarding the carrier frequency for autosomal recessive pathogenic variants among Syrian Jews. This report provides data to support carrier screening for a group of autosomal recessive conditions among Syrian Jews based on the population frequency of 40 different pathogenic variants in a cohort of over 3800 individuals with Syrian Jewish ancestry. METHODS: High throughput PCR amplicon sequencing was used to genotype 40 disease-causing variants in 3840 and 5279 individuals of Syrian and Iranian Jewish ancestry, respectively. These data were compared with Ashkenazi Jewish carrier frequencies for the same variants, based on roughly 370,000 Ashkenazi Jewish individuals in the Dor Yeshorim database. RESULTS: Carrier screening identified pathogenic variants shared among Syrian, Iranian, and Ashkenazi Jewish groups. In addition, alleles unique to each group were identified. Importantly, 8.2% of 3401 individuals of mixed Syrian Jewish ancestry were carriers for at least one pathogenic variant. CONCLUSION: The findings of this study support the clinical usefulness of premarital genetic screening for individuals with Syrian Jewish ancestry to reduce the incidence of autosomal recessive disease among persons with Syrian Jewish heritage.

Pathogenic gene variation spectrum and carrier screening for Wilson's disease in Qingdao area.

BACKGROUND: Despite the increasing number of reports on the analysis of ATP7B variants, reports on carrier screening for Wilson's disease (WD, OMIM:277900) are rare. METHODS: Peripheral blood samples were collected from 42 patients from Qingdao Women and Children's Hospital diagnosed with WD for direct sequencing of ATP7B gene. Twelve hotspot variants of ATP7B were selected for carrier screening in Qingdao area based on an analysis of information related to ATP7B variants and literature reports in China. We screened 5012 dried blood spots (DBSs) from asymptomatic newborns in Qingdao area to estimate carrier frequency. DNA was extracted from dried blood spots. Gene sequencing was performed using multiplex polymerase chain reaction (PCR) combined with second-generation sequencing. The carrier frequency of each hotspot variant was calculated using the count data (expressed as number of carriers (%) obtained by direct counting. RESULTS: The carrier frequency of 12 hotspot variants was 1.46% (95% CI: 1.16-1.83%). The ATP7B variant with the highest carrier frequency was c.2333G>T, accounting for 54.79% of all variants screened, followed by c.2975C>T and c.2621C>T, accounting for 17.81% and 15.07% of all variants screened, respectively. CONCLUSION: Carrier frequency of ATP7B gene pathogenic variants is high in the population in Qingdao area.

Randomized study of remote telehealth genetic services versus usual care in oncology practices without genetic counselors.

PURPOSE: To examine the benefit of telehealth over current delivery options in oncology practices without genetic counselors. METHODS: Participants meeting cancer genetic testing guidelines were recruited to this multi-center, randomized trial comparing uptake of genetic services with remote services (telephone or videoconference) to usual care in six predominantly community practices without genetic counselors. The primary outcome was the composite uptake of genetic counseling or testing. Secondary outcomes compare telephone versus videoconference services. RESULTS: 147 participants enrolled and 119 were randomized. Eighty percent of participants in the telehealth arm had genetic services as compared to 16% in the usual care arm (OR 30.52, p < 0.001). Five genetic mutation carriers (6.7%) were identified in the telehealth arm, compared to none in the usual care arm. In secondary analyses, factors associated with uptake were lower anxiety (6.77 vs. 8.07, p = 0.04) and lower depression (3.38 vs. 5.06, p = 0.04) among those who had genetic services. There were no significant differences in change in cognitive or affective outcomes immediately post-counseling and at 6 and 12 months between telephone and videoconference arms. CONCLUSION: Telehealth increases uptake of genetic counseling and testing at oncology practices without genetic counselors and could significantly improve identification of genetic carriers and cancer prevention outcomes.

ATTRv in Lazio-Italy: A High-Prevalence Region in a Non-Endemic Country.

Hereditary transthyretin amyloidosis (ATTRv, v for variant) prevalence in Italy, a non-endemic region, has been established by ATTRv amyloidosis Italian Registry. However, values of prevalence were extremely heterogeneous, considering different regions. To properly establish the prevalence of the disease in the Lazio region, a survey was sent to university regional hospitals and to main regional hospitals, in order to collect all affected patients regularly followed. We identified 100 ATTRv patients and, considering a Lazio population of 5.8/million, we estimated a ATTRv prevalence of 17.2/million. The ATTRv amyloidosis Italian Registry reported a prevalence of 8.0/million in Lazio, while our survey showed a value of double this. Our survey documented a high-prevalence for a non-endemic country. The increased awareness of the disease among general practitioners and medical specialists is a fundamental step to reduce the diagnostic delay and start an effective treatment of this disease.

Implementation of fragile X syndrome carrier screening during prenatal diagnosis: A pilot study at a single center.

BACKGROUND: Fragile X syndrome (FXS) is the most common inherited form of intellectual disability. Prenatal screening of FXS allows for early identification and intervention. The present study explored the feasibility of FXS carrier screening during prenatal diagnosis for those who were not offered screening early in pregnancy or prior to conception. METHODS: Pregnant women to be offered amniotic fluid testing were recruited for the free voluntary carrier screening at a single center between August, 2017 and September, 2019. The number of CGG repeats in the 5' un-translated region of the fragile X mental retardation gene 1 (FMR1) was determined. RESULTS: 4286 of 7000 (61.2%) pregnant women volunteered for the screening. Forty (0.93%), five (0.11%), and three (0.07%) carriers for intermediate mutation (45-54 repeats), premutation (55-200 repeats) and full mutation (>200 repeats) of the FMR1 gene were identified respectively. None of the detected premutation alleles were inherited by the fetuses. Of the three full mutation carrier mothers, all had a family history and one transmitted a full mutation allele to her male fetus. CONCLUSION: Implementation of FXS carrier screening during prenatal diagnosis may be considered for the need to increase screening for FXS.

Mainstream genetic testing for breast cancer patients: early experiences from the Parkville Familial Cancer Centre.

The demand for genetic testing of hereditary breast cancer genes such as BRCA1 and BRCA2 has continued to increase with the lowering costs of testing, raised awareness in the general public, and implications for breast cancer treatment when a patient is identified as having a germline pathogenic variant. Historically within Australia, patients affected by high genetic risk breast cancers have been referred to a familial cancer centre (FCC) for assessment and testing, resulting in wait times for an appointment for pre- and post-test genetic counselling and an increased demand on the public-funded FCC. To improve patient access and pace of genetic testing, as well as refocus FCC resources, a mainstream clinical genetic testing program was rolled out in September 2017 through the Parkville FCC (PFCC) in Australia at 10 hospital sites. This program enables specialist doctors of eligible patients affected by breast cancer to arrange genetic testing directly at an oncology/surgical appointment and follow up the results as part of the patients' routine clinical care. In this model, the specialist doctor is responsible for any treatment implications of the genetic test result, and the PFCC is responsible for result interpretation, future cancer risk, family cascade testing and segregation testing where warranted. To date the program has had successful uptake, a notable pathogenic variant detection rate, reduced the burden on the PFCC enabling a reallocation of resources and has streamlined the process of genetic testing for eligible patients. Investigation into the patient and clinician experiences of the mainstream program is required.

Evaluating the efficacy of three carrier screening workflows designed to identify at-risk carrier couples.

OBJECTIVE: To evaluate the efficacy of three different carrier screening workflows designed to identify couples at risk for having offspring with autosomal recessive conditions. METHODS: Partner testing compliance, unnecessary testing, turnaround time, and ability to identify at-risk couples (ARCs) were measured across all three screening strategies (sequential, tandem, or tandem reflex). RESULTS: A total of 314,100 individuals who underwent carrier screening were analyzed. Sequential, tandem, and tandem reflex screening yielded compliance frequencies of 25.8%, 100%, and 95.9%, respectively. Among 14,595 couples tested in tandem, 42.2% of females were screen-negative, resulting in unnecessary testing of the male partner. In contrast, less than 1% of tandem reflex couples included unnecessary male testing. The median turnaround times were 29.2 days (sequential), 8 days (tandem), and 13.3 days (tandem reflex). The proportion of ARCs detected per total number of individual screens were 0.5% for sequential testing and 1.3% for both tandem and tandem reflex testing. CONCLUSION: The tandem reflex strategy simplifies a potentially complex clinical scenario by providing a mechanism by which providers can maximize partner compliance and the detection of at-risk couples while minimizing workflow burden and unnecessary testing and is more efficacious than both sequential and tandem screening strategies.

Gene selection for the Australian Reproductive Genetic Carrier Screening Project ("Mackenzie's Mission").

Reproductive genetic carrier screening aims to offer couples information about their chance of having children with certain autosomal recessive and X-linked genetic conditions. We developed a gene list for use in "Mackenzie's Mission", a research project in which 10,000 couples will undergo screening. Criteria for selecting genes were: the condition should be life-limiting or disabling, with childhood onset, such that couples would be likely to take steps to avoid having an affected child; and/or be one for which early diagnosis and intervention would substantially change outcome. Strong evidence for gene-phenotype relationship was required. Candidate genes were identified from OMIM and via review of 23 commercial and published gene lists. Genes were reviewed by 16 clinical geneticists using a standard operating procedure, in a process overseen by a multidisciplinary committee which included clinical geneticists, genetic counselors, an ethicist, a parent of a child with a genetic condition and scientists from diagnostic and research backgrounds. 1300 genes met criteria. Genes associated with non-syndromic deafness and non-syndromic differences of sex development were not included. Our experience has highlighted that gene selection for a carrier screening panel needs to be a dynamic process with ongoing review and refinement.

NGS-based spinal muscular atrophy carrier screening of 10,585 diverse couples in China: a pan-ethnic study.

In this study, we performed a spinal muscular atrophy carrier screening investigation with NGS-based method. First, the validation for NGS-based method was implemented in 2255 samples using real-time PCR. The concordance between the NGS-based method and real-time PCR for the detection of SMA carrier and patient were up to 100%. Then, we applied this NGS-based method in 10,585 self-reported normal couples (34 Chinese ethnic groups from 5 provinces in South China) for SMA carrier screening. The overall carrier frequency was 1 in 73.8 (1.4%). It varied substantially between ethnic groups, highest in Dai ethnicity (4.3%), and no significant difference was found between five provinces. One couple was detected as carriers with an elevated risk of having an SMA affected baby. The distribution of SMN1:SMN2 genotype was also revealed in this study. Among the individuals with normal phenotype, the exon 7 copy-number ratio of SMN1 to SMN2 proved the gene conversion between them. With NGS-based method, we investigated SMA carrier status in Chinese population for the first time, and our results demonstrated that it is a promising alternative for SMA carrier screening and could provide data support and reference for future clinical application.

Examining the uptake of predictive BRCA testing in the UK; findings and implications.

Predictive BRCA testing is offered to asymptomatic individuals to predict future risk where a variant has been identified in a relative. It is uncertain whether all eligible relatives access testing, and whether this is related to health care inequalities. Our aim was to analyse trends and inequalities in uptake of testing, and identify predictors of testing and time-to-receipt of testing. A database from April 2010 to March 2017 was collated. Multivariate analysis explored individual associations with testing. Predictor variables included gender, BRCA test type, cancer history, Index of Multiple Deprivation (IMD) and education status. To evaluate factors associated with time-to-testing, a Cox proportional-hazards (CP) model was used. Of 779 tests undertaken, 336 (43.1%) were identified with a BRCA variant. A total of 537 (68.9%) were female and in 83.4% (387/464) of probands, predictive testing was received by relatives. Analysis identified inequalities since decreased testing was found when the proband was unaffected by cancer (OR 0.14, 95% CI 0.06-0.33). Median time-to-testing was 390 days (range, 0-7090 days) and the CP model also identified inequalities in the hazard ratio (HR) for testing for people aged >40 was higher than for aged <40 (HR 1.41, 95% CI 1.20-1.67) and BRCA2 testing was higher than for BRCA1 testing (HR 1.39, 95% CI 1.18-1.64). Reduced testing was found when probands were unaffected by cancer and time-to-testing was found to vary by age and BRCA1/2 test. Given limited study sample size, further research is recommended to examine inequalities in predictive BRCA testing.

Parental exome analysis identifies shared carrier status for a second recessive disorder in couples with an affected child.

Consanguinity, commonplace in many regions around the globe, is associated with an increased risk of autosomal recessive (AR) genetic disorders. Consequently, consanguineous couples undergoing preimplantation genetic diagnosis (PGD) for one Mendelian disorder may be at increased risk for a child with a second, unrelated AR genetic disorder. We examined the yield of exome analysis for carrier screening of additional AR disorders, beyond the primary diagnosis, amongst consanguineous vs. non-consanguineous populations. Parental samples from trio exomes of 102 consanguineous families and 105 non-consanguineous controls were evaluated for shared carrier status, after disregarding the primary molecular diagnosis. Results were sub-classified according to disease severity. Secondary shared carrier status for pathogenic and likely pathogenic variants leading to AR disorders of moderate to profound severity was identified in 10/102 (9.8%) consanguineous couples, as compared to 1/105 (0.95%) non-consanguineous couples (χ2 = 8.0565, p value < 0.005). Higher inbreeding coefficient values, calculated from individual exomes, correlated with secondary shared carrier status for diseases of moderate to profound severity (r = 0.17, p value < 0.0125). Our results indicate that consanguineous couples undergoing PGD are at increased risk for a second genetic disease of moderate to profound severity. This study represents an underestimate of the rate of secondary shared carrier status due to inability to detect deep intronic variants, no assessment of copy number variants, and false negative results stemming from stringent variant interpretation. False positive results may result from inaccuracies in public databases. Additional studies in consanguineous populations will determine whether exome-based carrier screening should be recommended to all couples undergoing PGD.

Reproductive male partner testing when the female is identified to be a genetic disease carrier.

OBJECTIVE: To quantify carrier testing uptake rates for male partners of women found to be a carrier(s) for autosomal recessive conditions and to understand reasons for declining testing (uptake rate). METHODS: A retrospective chart review of 513 female patients seen at Rutgers-Robert Wood Johnson Medical School found to be carriers through expanded carrier screening (ECS) panels. The aims of this study were to determine how often their male partner chose testing, reasons for declining and the type of methodology chosen for their screening. RESULTS: Male partner uptake rate was 77%. We identified that the most significant barrier to male partner testing is female patients not following up on their own carrier screening results, thus missing the opportunity for partner testing. When male partners were provided options for testing, the most reported reason for declining is the belief it would have no impact on pregnancy management (20%). A carrier couple rate of 8.3% was identified of partners tested. CONCLUSION: Despite a relatively high male testing uptake rate, a quarter of carrier females did not proceed with testing their partner. To ascertain fetal risk, results for both parents is necessary. Pretest counseling should stress need for potential male partner follow-up testing.

NGS-based expanded carrier screening for genetic disorders in North Indian population reveals unexpected results - a pilot study.

BACKGROUND: To determine the carrier frequency and pathogenic variants of common genetic disorders in the north Indian population by using next generation sequencing (NGS). METHODS: After pre-test counselling, 200 unrelated individuals (including 88 couples) were screened for pathogenic variants in 88 genes by NGS technology. The variants were classified as per American College of Medical Genetics criteria. Pathogenic and likely pathogenic variants were subjected to thorough literature-based curation in addition to the regular filters. Variants of unknown significance were not reported. Individuals were counselled explaining the implications of the results, and cascade screening was advised when necessary. RESULTS: Of the 200 participants, 52 (26%) were found to be carrier of one or more disorders. Twelve individuals were identified to be carriers for congenital deafness, giving a carrier frequency of one in 17 for one of the four genes tested (SLC26A4, GJB2, TMPRSS3 and TMC1 in decreasing order). Nine individuals were observed to be carriers for cystic fibrosis, with a frequency of one in 22. Three individuals were detected to be carriers for Pompe disease (frequency one in 67). None of the 88 couples screened were found to be carriers for the same disorder. The pathogenic variants observed in many disorders (such as deafness, cystic fibrosis, Pompe disease, Canavan disease, primary hyperoxaluria, junctional epidermolysis bullosa, galactosemia, medium chain acyl CoA deficiency etc.) were different from those commonly observed in the West. CONCLUSION: A higher carrier frequency for genetic deafness, cystic fibrosis and Pompe disease was unexpected, and contrary to the generally held view about their prevalence in Asian Indians. In spite of the small sample size, this study would suggest that population-based carrier screening panels for India would differ from those in the West, and need to be selected with due care. Testing should comprise the study of all the coding exons with its boundaries in the genes through NGS, as all the variants are not well characterized. Only study of entire coding regions in the genes will detect carriers with adequate efficiency, in order to reduce the burden of genetic disorders in India and other resource poor countries.

Frequency of heterozygous germline pathogenic variants in genes for Fanconi anemia in patients with non-BRCA1/BRCA2 breast cancer: a meta-analysis.

PURPOSE: Germline pathogenic variants in BRCA1 (FANCD1) and BRCA2 (FANCS) do not explain all familial or sporadic cases with breast cancer. Several reports indicate a role for pathogenic variants in other genes in the Fanconi anemia/breast cancer DNA repair pathway; the strengths of these associations vary widely. Publications from 2006 through 2017 were reviewed to provide a better estimate of the role of pathogenic variants in genes in this pathway in breast cancer. METHODS: We identified cohorts and case-control reports describing heterozygous pathogenic variants in Fanconi anemia genes in breast cancer cases with high risk of a germline pathogenic variant in a non-BRCA1/2 breast cancer susceptibility gene ("familial"), and cases unselected for family history ("unselected"). Meta-analysis and meta-regression were used to estimate the frequencies of pathogenic variants in cohorts and the odds ratios (OR) in case-control studies. RESULTS: Meta-analysis of more than 100 reports of FANCN/PALB2 in familial breast cancer cases provided an overall pathogenic variant prevalence of 1.29% and an OR of 8.45. The prevalence in unselected cohorts was 0.64%, and the OR was 4.76. Pathogenic variants in FANCJ/BRIP1 had a prevalence of 0.5% in familial cases, and an OR of 1.62; their prevalence in unselected cases was 0.39%. FANCO/RAD51C, FANCP/SLX4, FANCU/XRCC2, FANCD2, and other FA-related genes all had prevalences of ≤ 0.5% among familial cases, and even lower in unselected cases. CONCLUSIONS: Heterozygous pathogenic variants in FANCN/PALB2 and possibly FANCJ/BRIP1 may account for 1-2% of familial non-BRCA1/2 breast cancer cases and 0.5-1% of unselected cases. Genetic counseling and testing may be suggested for unaffected relatives.

Web-based return of BRCA2 research results: one-year genetic counselling experience in Iceland.

There is an increased pressure to return results from research studies. In Iceland, deCODE Genetics has emphasised the importance of returning results to research participants, particularly the founder pathogenic BRCA2 variant; NM_000059.3:c.771_775del. To do so, they opened the website www.arfgerd.is . Individuals who received positive results via the website were offered genetic counselling (GC) at Landspitali in Reykjavik. At the end of May 2019, over 46.000 (19% of adults of Icelandic origin) had registered at the website and 352 (0.77%) received text message informing them about their positive results. Of those, 195 (55%) contacted the GC unit. Additionally, 129 relatives asked for GC and confirmatory testing, a total of 324 individuals. Various information such as gender and age, prior knowledge of the variant and perceived emotional impact, was collected. Of the BRCA2 positive individuals from the website, 74 (38%) had prior knowledge of the pathogenic variant (PV) in the family. The majority initially stated worries, anxiety or other negative emotion but later in the process many communicated gratitude for the knowledge gained. Males represented 41% of counsellees as opposed to less than 30% in the regular hereditary breast and ovarian (HBOC) clinic. It appears that counselling in clinical settings was more reassuring for worried counsellees. In this article, we describe one-year experience of the GC service to those who received positive results via the website. This experience offers a unique opportunity to study the public response of a successful method of the return of genetic results from research.

Expanded carrier screening in Chinese patients seeking the help of assisted reproductive technology.

BACKGROUND: Expanded carrier screening (ECS) has emerged as an effective approach to identify at-risk couples (ARCs)-before they initiate attempts at reproduction-who possess a high probability of having a child affected by severe recessive diseases. The objective of this study was to evaluate the clinical utility of ECS in Chinese patients seeking the help of assisted reproductive technology (ART). METHODS: An ECS test, which covers 201 genes implicated in 135 recessive (autosomal or X-linked) diseases, was routinely offered to all ART patients in a single genetics and in vitro fertilization clinic. Additional options for preimplantation or prenatal genetic diagnosis were discussed and offered to all ARCs. All ECS results were aggregated and the clinical decisions of the ARCs were surveyed. RESULTS: A total of 2,923 ART patients, representing 1,462 couples, were screened. Overall, 46.73% of the individuals were found to be the carriers for at least 1 of the 135 diseases. Of the tested couples, 2.26% (n = 33) were identified as ARCs. As of the completion of this study, 21 (63.6%) ARCs have decided to avert an affected pregnancy with the help of preimplantation genetic testing for monogenetic conditions. The cumulative carrier rate of the 187 autosomal recessive genes in the ECS panel for the 2,836 Han Chinese individuals without a family history was estimated to be 45.91%. The estimated at-risk couple rate indicates that the screening for only the top 31 genes with gene carrier rates >0.5% would identify more than 94% of the ARCs identified by screening all 187 genes. CONCLUSION: Our study demonstrates that ESC yields a significant clinical value for ART patients in China. In addition, by estimating the yields of the ECS panel, we identify genes that are appropriate for screening the Han population.