Cystic Fibrosis Carrier Screening Research Articles

Cystic fibrosis carrier screening: a Health technology assessment.

This project of Health technology assessment was aimed at defining the impacts of offering a cystic fibrosis (CF) carrier screening to the general population, compared to the current situation, where the test is offered to individuals at high-risk to give birth to a child with CF. Results revealed: i) a lack of robust and updated data; ii) a return on investment up to six years from the screening's introduction, despite important economic and organizational efforts; iii) a general positive attitude of healthcare professionals, people with CF, families and general population; iv) possible issues related to the social impact.

The new face of cystic fibrosis in the era of population genetic carrier screening

BackgroundPopulation genetic carrier screening (PGCS) for cystic fibrosis (CF) has been offered to couples in Israel since 1999 and was included in a fully subsidized national program in 2008. We evaluated the impact of PGCS on CF incidence, genetic and clinical features. MethodsThis was a retrospective national study. Demographic and clinical characteristics of children with CF born in Israel between 2008 and 2018 were obtained from the national CF registry and from patients' medical records. Data on CF births, preimplantation genetic testing (PGT), pregnancy termination and de-identified data from the PGCS program were collected. ResultsCF births per 100,000 live births decreased from 8.29 in 2008 to 0.54 in 2018 (IRR = 0.84, p < 0.001). The CF pregnancy termination rate did not change (IRR = 1, p= 0.9) while the CF-related PGT rate increased markedly (IRR = 1.33, p < 0.001). One hundred and two children were born with CF between 2008 and 2018 with a median age at diagnosis of 4.8 months, range 0–111 months. Unlike the generally high uptake nationally, 65/102 had not performed PGCS. Even if all had utilized PGCS, only 51 would have been detected by the existing genetic screening panel. Clinically, 34 % of children were pancreatic sufficient compared to 23 % before 2008 (p = 0.04). ConclusionsSince institution of a nationwide PGCS program, the birth of children with CF decreased markedly. Residual function variants and pancreatic sufficiency were more common. A broader genetic screening panel and increased PGCS utilization may further decrease the birth of children with CF.

Efficacia dello screening preconcezionale del portatore di fibrosi cistica: revisione sistematica.

genetic testing for cystic fibrosis (CF) has been offered to people with higher risk of being carrier. to assess the effectiveness of population-based CF carrier screening for adults of reproductive age and its optimal organizational features. systematic review. MedLine, Embase, Cochrane Library, CINAHL and LILACS (1990-2022) were searched to retrieve primary and secondary studies on adults (16 years and older), with no clinical indication or genetic risk, eligible for genetic testing for CF carrier status. attitude to screening, uptake of screening offered, informed reproductive choices. a total of 3,326 records were screened and 292 potentially eligible full-text publications assessed. The review included 71 publications, corresponding to 3 reviews, 40 cohort studies (11 comparative, 29 single-arm), and 6 model studies, published between 1992 and 2021 (median 1998). Only one study compared screening or no screening. This study suggested an association between carrier screening and a lower incidence of CF. Comparative studies examined different approaches for invitation and testing, i.e., settings, target population (individuals/couples, prenatal/preconceptional), how invitations are organized (primary care/maternal hospitals), and format and content of the pre-test information. However, no firm conclusions can be drawn on the impact of these features on informed reproductive choices, uptake, and attitude, because of the limitations of the evidence collected. the broad heterogeneity of the studies, methodological weaknesses, and the limited transferability of the results mean there is still uncertainty about the effectiveness of preconceptional and prenatal CF carrier screening in the general population.

International experience in the primary prevention of cystic fibrosis (part two)

This text is a continuation of a review of international studies and guidelines/recommendations for primary prevention of cystic fibrosis (CF). This section reviews the selection of pathogenic variants for different CF mutation carrier screening programmes to form panels, taking into account the geographical and ethnic characteristics of the couples being screened, describes the monitoring of couples at intermediate risk of carrier, presents the relationship between carrier screening and neonatal screening, highlights the importance of timely information, including medical and genetic counselling for stakeholders, taking into account the psychosocial status. Separately, we present studies that have found a reduction in the rate of CF births in France, Italy and Israel after the introduction of CF carrier screening.

Maternal carrier screening with single-gene NIPS provides accurate fetal risk assessments for recessive conditions

PurposeThe purpose of this study was to evaluate the clinical performance of carrier screening for cystic fibrosis, hemoglobinopathies, and spinal muscular atrophy with reflex single-gene noninvasive prenatal screening (sgNIPS), which does not require paternal carrier screening. MethodsAn unselected sample of 9151 pregnant individuals from the general US pregnant population was screened for carrier status, of which 1669 (18.2%) were identified as heterozygous for one or more pathogenic variants and reflexed to sgNIPS. sgNIPS results were compared with newborn outcomes obtained from parent survey responses or provider reports for a cohort of 201 pregnancies. ResultsOverall, 98.7% of pregnant individuals received an informative result (no-call rate = 1.3%), either a negative carrier report or, if identified as heterozygous for a pathogenic variant, a reflex sgNIPS report. In the outcomes cohort, the negative predictive value of sgNIPS was 99.4% (95% CI = 96.0%-99.9%) and average positive predictive value (PPV) of sgNIPS was 48.3% (95% CI = 36.1%-60.1%). Importantly, personalized PPVs accurately reflected the percentage of affected pregnancies in each PPV range, and all pregnancies with a sgNIPS fetal risk of >9 in 10 (90% PPV) were affected. ConclusionAlthough traditional carrier screening is most effective when used to assess reproductive risk before pregnancy, more than 95% of the time it is pursued during a pregnancy and is complicated by incomplete uptake of paternal carrier screening (<50%) and misattributed paternity (∼10%). Even in an idealized setting, when both partners have carrier screening, the maximum risk for having an affected pregnancy is 1 in 4 (equivalent of a 25% PPV). Carrier screening with sgNIPS during pregnancy is an alternative that does not require a paternal sample and provides accurate fetal risk in a timely manner that can be used for prenatal counseling and pregnancy management.

Guidelines for Cystic Fibrosis Carrier Screening in the Prenatal/Preconception Period.

Cystic fibrosis (CF) is one of the most common autosomal recessive disorders. Carrier screening for CF should be offered to all women considering becoming pregnant or who are pregnant. Understanding the available screening tests, their limitations, and the benefits of screening is of paramount importance to the obstetrician-gynecologist. The objective is to review the current guidelines for CF carrier screening including the options for carrier screening, the potential complexities associated with carrier screening for CF, and indications for referral to certified genetic counselors or maternal-fetal medicine specialists. A MEDLINE search of "cystic fibrosis," "cystic fibrosis carrier screening pregnancy," and "inheritance of cystic fibrosis" in the review was performed. The evidence cited in this review includes 2 medical society committee opinions and 15 additional peer-reviewed journal articles that were original research or expert opinion summaries. The American College of Obstetricians and Gynecologists recommends that obstetricians offer CF carrier screening to all pregnant women or women considering becoming pregnant. Based on recent guidelines from ACMG, additional expanded carrier screening can be recommended to patients in the future, with additional CF variants and other autosomal or X-linked recessive conditions. It is important for the prenatal care provider to understand the guidelines for carrier screening as well as the potential complexities associated with carrier screening due to the multiple pathogenic variants in the CFTR gene that may be associated with varying phenotypes. With the options for CF carrier screening, screening performance in different populations, a basic understanding of the disease and interpretation of carrier screening results is of paramount importance to the prenatal care provider.

Reproductive genetic carrier screening for cystic fibrosis, fragile X syndrome and spinal muscular atrophy: patterns of community and healthcare provider participation in a Victorian screening program.

The Royal Australian and New Zealand College of Obstetricians and Gynaecologists and The Royal Australian College of General Practice recommend that information on carrier screening for at least the most common inherited genetic conditions in our population, that is, thalassaemia, cystic fibrosis (CF), spinal muscular atrophy (SMA), and fragile X syndrome (FXS), should be offered to all women planning pregnancy or in early pregnancy regardless of family history or ethnicity. The aim of this study was to investigate patterns of participation by healthcare providers (HCP) and the community in screening. Participation in a Victorian program screening for CF, SMA and FXS between September 2013 and October 2018 was analysed. Requesting HCP and patient data were extracted from screening request forms. Data were analysed with respect to profession of requesting HCP, and characteristics of women screened (age, pregnancy status, socioeconomic status, geographic location, and family history of CF, SMA or FXS). In total, 21 172 women and 1288 HCPs participated in the program over this period. There was a steep socioeconomic gradient in screening uptake, with nearly half the women screened (10 349) being in the highest socioeconomic quintile. The screening rate was much higher in metropolitan areas than in regional areas. Obstetricians made most of the requests for screening, whereas 20% of requests were by GPs. Most participating GPs only made a single screening request (78%) and very few GPs made >100 screening requests compared with obstetricians (0.2% vs 17%). GPs were more likely to screen women before pregnancy compared with obstetricians (47% vs 11%). Approximately 1.5% of Victorian women of child-bearing age and 3% of pregnant Victorian women were screened by this program over the period of this study. This study highlights the translation gap between recommendations and practice, with marked inequity of access to reproductive genetic carrier screening in relation to socioeconomic status and geography. Increased participation by GPs could improve community access to reproductive genetic carrier screening, particularly access to preconception screening. Addressing the causes of inequity of access will allow more women and couples the opportunity to make informed choices about participation in screening.

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

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. 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. 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. 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.

Genetic Carrier Screening for Cystic Fibrosis, Fragile X Syndrome, Hemoglobinopathies, and Spinal Muscular Atrophy

&#x0D; People generally describe wanting access to carrier screening because knowing about the risk of passing along a genetic condition is considered important and supportive of their desires to be prepared. In the context of expanded carrier screening programs, this could mean that an increased number of people would want to access these programs.&#x0D; Supporting people who are considering carrier screening can be challenging and is likely to be more involved than simply sharing high-level descriptive information about testing details and potential outcomes. Descriptive information is important to help people understand the screening process and the types of results that could emerge from testing; however, programs might be more supportive of informed decision-making if the providers take a proactive role and are open to facilitating speculative conversations about potential ramifications in people’s actual lives. This is challenging given the expressed desire by health care providers, clinical geneticists in particular, to provide “neutral information” that patients would not experience as prescriptive.&#x0D; Given the challenge of supporting people making decisions about whether or not to pursue carrier screening, and the likely increase in people who would consider carrier screening if targeted programs were expanded to population-level screening, it is important to ensure that health care providers are both aware of jurisdictional carrier screening programs and competent in what carrier screening can offer their patients in terms of clinical actionability. Although this is particularly true for general practitioners who are often the primary point of contact with the health care system for their patients, it is also important for people who work in family planning clinics and women’s health clinics.&#x0D; Having the option to engage with carrier screening at the preconception stage was universally preferred by participants across the included studies. Compared with prenatal carrier screening, preconception carrier screening was seen as providing prospective parents with more reproductive options. Health care providers were concerned that offering carrier screening during pregnancy might lead pregnant people and their partners to confuse it with other prenatal testing which would limit people’s ability to be truly informed before deciding whether or not to pursue screening. However, if offered as a prenatal option, most people consider it important to do so as early as possible because it could be paired with other prenatal tests. Although not referred to specifically by any of the included studies, we note that offering carrier screening prenatally rather than at preconception, could place the responsibility to make the decision on cisgender women and non-binary or transgender people with uteruses.&#x0D; Sequentially designed carrier screening programs were the most common across the included studies; however, people moving through programs with this design found the interim period between receiving their positive carrier results and receiving their partners’ results difficult. This was particularly true for people who were already pregnant because this interim period forced them to reimagine both their relationship with the fetus and the future they had imagined with that child. Of course, this reimagining might be necessary if both partners’ screening results came back positive for the condition in question, but to stagger the return of the results could put undue anxiety on potential parents.&#x0D; Carrier screening will not affect everyone in the same way, and reproductive decision-making will still be complex and difficult. As such, the opportunity to engage with genetic counsellors on reproductive options following positive carrier status result is considered valuable.&#x0D;

Factors influencing medical practitioner participation in population carrier screening for cystic fibrosis.

Cystic fibrosis (CF) carrier screening should be offered to people planning a pregnancy or in early pregnancy, according to current recommendations. However, research indicates rates of offering CF carrier screening are low. Health professionals (HPs) play an important role in offering population carrier screening. To determine the opinions, knowledge and practice patterns of HPs with regard to the routine offering of population carrier screening for CF. Five key informant interviews informed the development of an online questionnaire which was distributed to a select group of HPs involved in prenatal care in Victoria, Australia. Of the participants who completed the questionnaire (n=87), 35.6% reported offering CF carrier screening to all patients attending for preconception or early pregnancy consultations. High referrers of CF carrier screening were more likely to be female, work in the private sector, in metropolitan areas and specialise as an obstetrician. High referrers demonstrated a greater level of knowledge of CF and carrier screening than low referrers (t=-3.779, P<0.001). Low referrers perceived more barriers to offering carrier screening than high referrers (t=2.125, P=0.037). Low referrers were more likely to perceive lack of community awareness and HP knowledge as a barrier to offering CF carrier screening, compared to high referrers, who were more likely to perceive time constraints as a barrier. To promote routine offering of population CF carrier screening, resources are needed to improve knowledge and provide clinical support thereby reducing perceived barriers.

Molecular Diagnosis and Genetic Counseling of Cystic Fibrosis and Related Disorders: New Challenges.

Identification of the cystic fibrosis transmembrane conductance regulator (CFTR) gene and its numerous variants opened the way to fantastic breakthroughs in diagnosis, research and treatment of cystic fibrosis (CF). The current and future challenges of molecular diagnosis of CF and CFTR-related disorders and of genetic counseling are here reviewed. Technological advances have enabled to make a diagnosis of CF with a sensitivity of 99% by using next generation sequencing in a single step. The detection of heretofore unidentified variants and ethnic-specific variants remains challenging, especially for newborn screening (NBS), CF carrier testing and genotype-guided therapy. Among the criteria for assessing the impact of variants, population genetics data are insufficiently taken into account and the penetrance of CF associated with CFTR variants remains poorly known. The huge diversity of diagnostic and genetic counseling indications for CFTR studies makes assessment of variant disease-liability critical. This is especially discussed in the perspective of wide genome analyses for NBS and CF carrier screening in the general population, as future challenges.

International perspectives on the implementation of reproductive carrier screening.

Reproductive carrier screening started in some countries in the 1970s for hemoglobinopathies and Tay-Sachs disease. Cystic fibrosis carrier screening became possible in the late 1980s and with technical advances, screening of an ever increasing number of genes has become possible. The goal of carrier screening is to inform people about their risk of having children with autosomal recessive and X-linked recessive disorders, to allow for informed decision making about reproductive options. The consequence may be a decrease in the birth prevalence of these conditions, which has occurred in several countries for some conditions. Different programs target different groups (high school, premarital, couples before conception, couples attending fertility clinics, and pregnant women) as does the governance structure (public health initiative and user pays). Ancestry-based offers of screening are being replaced by expanded carrier screening panels with multiple genes that is independent of ancestry. This review describes screening in Australia, Cyprus, Israel, Italy, Malaysia, the Netherlands, Saudi Arabia, the United Kingdom, and the United States. It provides an insight into the enormous variability in how reproductive carrier screening is offered across the globe. This largely relates to geographical variation in carrier frequencies of genetic conditions and local health care, financial, cultural, and religious factors.

Sequencing as a first-line methodology for cystic fibrosis carrier screening

PurposeMedical society guidelines recommend offering genotyping-based cystic fibrosis (CF) carrier screening to pregnant women or women considering pregnancy. We assessed the performance of sequencing-based CF screening relative to genotyping, in terms of analytical validity, clinical validity, clinical impact, and clinical utility. MethodsAnalytical validity was assessed using orthogonal confirmation and reference samples. Clinical validity was evaluated using the CFTR2 database. Clinical impact was assessed using ~100,000 screened patients. Three screening strategies were compared: genotyping 23 guideline-recommended variants (“CF23”), sequencing all coding bases in CFTR (“NGS”), and sequencing with large copy-number variant (CNV) identification(“NGS + CNV”). Clinical utility was determined via self-reported actions of at-risk couples (ARCs). ResultsAnalytical accuracy of NGS + CNV was 100% for SNVs, indels, and CNVs; interpretive clinical specificity relative to CFTR2 was 99.5%. NGS + CNV detected 58 ARCs, 18 of whom would have gone undetected with CF23 alone. Most ARCs (89% screened preconceptionally, 56% prenatally) altered pregnancy management, and no significant differences were observed between ARCs with or without at least one non-CF23 variant. ConclusionModern NGS and variant interpretation enable accurate sequencing-based CF screening. Limiting screening to 23 variants does not improve analytical validity, clinical validity, or clinical utility, but does fail to detect approximately 30% (18/58) of ARCs.

Variations in prenatal screening in a US federal healthcare system: Same coverage, different options.

The Military Health System (MHS) is a federally funded organization that provides care to active duty service members and their beneficiaries. Our objective was to determine what methods of prenatal screening are used by military treatment facilities (MTFs), assess variations between institutions, and determine how practice patterns align with national recommendations. We surveyed all MTFs offering comprehensive prenatal care (n=49). Departments were asked about aneuploidy screening options, availability of diagnostic testing, and carrier screening. In all, 43 MTFs (88%) completed the survey. Most (39/43) patients were stratified based on risk (predominantly maternal age at delivery and history). The most commonly offered test was combined 1st/2nd trimester screening (59%). Sixty percent routinely offered diagnostic testing, though less than half routinely offered microarrays. The majority offered universal carrier screening for cystic fibrosis (98%) and complete blood count with screening for thalassemias and hemoglobinopathies (88%). At the time of data collection, only five facilities (12%) had implemented spinal muscular atrophy carrier screening. Considerable heterogeneity exists in prenatal aneuploidy testing and carrier screening within the MHS. Standardized guidelines, protocols, and laboratory support would improve processes across the system. Additional resources including genetic counseling support and provider education are needed.

Population genomic screening of all young adults in a health-care system: a cost-effectiveness analysis

PurposeTo consider the impact and cost-effectiveness of offering preventive population genomic screening to all young adults in a single-payer health-care system. MethodsWe modeled screening of 2,688,192 individuals, all adults aged 18–25 years in Australia, for pathogenic variants in BRCA1/BRCA2/MLH1/MSH2 genes, and carrier screening for cystic fibrosis (CF), spinal muscular atrophy (SMA), and fragile X syndrome (FXS), at 71% testing uptake using per-test costs ranging from AUD$200 to $1200 (~USD$140 to $850). Investment costs included genetic counseling, surveillance, and interventions (reimbursed only) for at-risk individuals/couples. Cost-effectiveness was defined below AUD$50,000/DALY (disability-adjusted life year) prevented, using an incremental cost-effectiveness ratio (ICER), compared with current targeted testing. Outcomes were cancer incidence/mortality, disease cases, and treatment costs reduced. ResultsPopulation screening would reduce variant-attributable cancers by 28.8%, cancer deaths by 31.2%, and CF/SMA/FXS cases by 24.8%, compared with targeted testing. Assuming AUD$400 per test, investment required would be between 4 and 5 times higher than current expenditure. However, screening would lead to substantial savings in medical costs and DALYs prevented, at a highly cost-effective ICER of AUD$4038/DALY. At AUD$200 per test, screening would approach cost-saving for the health system (ICER=AUD$22/DALY). ConclusionPreventive genomic screening in early adulthood would be highly cost-effective in a single-payer health-care system, but ethical issues must be considered.

Sequencing-Based Carrier Screening for Cystic Fibrosis: Ready for Prime Time? [16O

Sequencing-Based Carrier Screening for Cystic Fibrosis: Ready for Prime Time? [16O

Spinal Muscular Atrophy: Ordering Trends Pre- and Post-ACOG Committee Opinion 691 [17O

INTRODUCTION: Spinal muscular atrophy (SMA) is a leading inherited cause of infant death and is second to cystic fibrosis (CF) as a common, life-limiting autosomal recessive disorder. In March 2017, the American College of Obstetrics and Gynecology (ACOG) released a committee opinion (691) stating that screening for SMA should be offered to all patients considering pregnancy or currently pregnant. METHODS: To assess the uptake of SMA screening following the ACOG recommendations, a retrospective analysis of tests ordered from healthcare practices for single gene carrier screening of SMA and CF was performed. Data were analyzed over two equal time periods pre- and post-March 2017. RESULTS: Data were collected from nearly 4,000 healthcare providers who ordered at least one SMA test in the study period. The average number of monthly tests ordered per practice was six pre-ACOG opinion, and 16.7 post-ACOG opinion. Over 50% of practices did not order SMA testing prior to the ACOG opinion. Among practices regularly ordering testing for CF there was an increase in testing for SMA post-opinion, however, the number of CF tests received was 27% higher than SMA tests received. CONCLUSION: Carrier screening for SMA increased more than two and half times post ACOG opinion, likely due to the new recommendations. Despite the increase in SMA carrier tests, the number of SMA tests post-opinion did not match the number of CF tests from healthcare practices sending both tests to our laboratory. These findings suggest increased adoption of SMA screening guidelines but still not at the level observed for CF.

886: Detection of copy-number variants in expanded carrier screening maximizes identification of cystic fibrosis carriers

Cystic fibrosis is one of the most common autosomal recessive conditions. Medical-society guidelines recommend routine carrier screening for cystic fibrosis via targeted genotyping of 23 frequent single-nucleotide variants (SNVs) and short insertions or deletions (indels) in the CFTR gene. Screening for copy-number variants (CNVs) is recommended only when a reproductive partner is a known carrier. Here we assess the performance and clinical impact of routinely screening for SNVs, indels, and CNVs in a next-generation sequencing (NGS)-based expanded carrier screen (ECS). Pathogenic variants in CFTR from 103,718 patients were discovered via a validated NGS-based ECS. A custom algorithm identified CNVs via relative deviations in NGS read depth. Approximate CNV breakpoints were inferred from the NGS-depth profile. Positive CNVs were orthogonally assessed via multiplex ligation-dependent probe amplification (MLPA). CFTR CNV sensitivity was explored across a range of length scales via in silico simulations. Among carriers of cystic fibrosis, 98.7% had pathogenic SNVs or indels in the CFTR gene (79% had one of the 23 common variants), and the remaining 1.3% harbored a pathogenic CNV spanning at least one exon. In total, we observed 25 unique CNVs with a diversity of breakpoints, suggesting that algorithms must be configured to detect novel CNVs. Further, single-exon deletions were observed for seven different CFTR exons; analysis of confidence scores for these empirical deletions—coupled with extensive simulations—demonstrated that the bioinformatics pipeline was both accurate and robust, even for short CNVs. All CNVs identified via NGS were confirmed via MLPA. CNV detection maximizes identification of cystic fibrosis carriers and can be applied to all patients undergoing an NGS-based ECS test validated to detect these complicated variants. Clinical guidelines recommending screening of only the 23 most frequent variants miss critical identification of carriers and should be revisited.

Functional characterization and phenotypic spectrum of three recurrent disease-causing deep intronic variants of the CFTR gene

BackgroundThe CFTR genotype remains incomplete in 1% of Cystic Fibrosis (CF) cases, because only one or no disease-causing variants is detected after extended analysis. This fraction is probably higher in CFTR-Related Disorders (CFTR-RD). Deep-intronic CFTR variants are putative candidates to fill this gap. However, the recurrence, phenotypic spectrum and full molecular characterization of newly reported variants are unknown. MethodsMinigenes and analysis of CFTR transcripts in nasal epithelial cells were used to determine the impact on CFTR splicing of intronic variants that we previously identified by next generation sequencing of the whole CFTR locus. Phenotypic data were collected in 19 patients with CF and CFTR-RD, in whom one of the deep intronic variants has been detected. ResultsThree deep-intronic variants promoted the inclusion of pseudo-exons (PE) in the CFTR transcript, hindering the synthesis of a functional protein. The c.2989-313A > T variant, detected in four patients with CF or CFTR-RD from three different families, led to the inclusion of a 118 bp PE. The c.3469-1304C > G variant promoted the inclusion of a 214 bp-PE and was identified in five patients with CF from four families. Haplotype analysis confirmed that this variant was associated with one CF chromosome of African origin. The most represented variant in our cohort was the c.3874-4522A > G, detected in 10 patients with various phenotypes, from male infertility to CF with pancreatic insufficiency. ConclusionThese three deep intronic CFTR variants are associated with a large phenotypic spectrum, including typical CF. They should be included in CF diagnostic testing and carrier screening strategies.

Direct-to-consumer carrier screening for cystic fibrosis via a hospital website: a 6-year evaluation

A Dutch university hospital started offering cystic fibrosis (CF) carrier screening directly to consumers (DTC) through their website in 2010. A 6-year process evaluation was conducted to evaluate the offer. Screening was implemented as intended. However, uptake was lower than expected. Forty-four tests have been requested, partly by couples with a positive family history for CF, which was not the intended target group. Users were generally positive about the screening offer, citing accessibility, ease of testing, anonymity, and perceived shortcomings of regular healthcare as reasons for requesting screening. DTC CF carrier screening via a university hospital website is feasible, but is seldom used. Considering technological advances, continuation of this specific offer is questionable.