Preconceptional cystic fibrosis carrier screening: opinions of general practitioners, gynecologists, and pediatricians in the Netherlands

Knowledge of the opinions of physicians with regard to preconceptional cystic fibrosis (CF) carrier screening and the possible factors that are associated with their opinions is important for the implementation of such a screening program. Data were obtained from a study in which genetic knowledge, opinions with regard to genetic testing and related skills were investigated. A questionnaire, developed and used by American researchers, was adapted to the Dutch health care situation, and sent to randomly selected general practitioners (GPs) (n = 200), gynecologists (GYNs) (n = 300), and pediatricians (PEDs) (n = 265). In this part of the study, their opinions with regard to genetic preconceptional CF carrier screening in different situations were assessed. The response rate for the GPs, GYNs, and PEDs was 64%, 69%, and 72%, respectively. In total, 63% of the GPs, 69% of the GYNs and 72% of the PEDs supported preconceptional CF carrier testing if a couple requested a test. Sixteen percent, 19% and 25%, respectively, were in favor of actively offering a test with 95% test sensitivity to all couples who were planning a pregnancy. A positive opinion on preconceptional CF carrier screening was associated with the following variables: "considering the test sensitivity as less important" (GPs, GYNs), "high perceived risk of having a child with CF" (GYNs), "providing genetic counselling in their own practice" (PEDs) and "reassurance when both partners test negative" (PEDs). Physicians are sympathetic toward preconceptional CF carrier screening if the couples themselves request a test. Physicians had reservations about routinely offering a CF carrier test.     

Cystic fibrosis carrier population screening in the primary care setting.

To determine the receptivity of prenatal care providers and their patients to carrier testing for cystic fibrosis (CF), we offered free carrier screening, followed by genetic counseling of carriers, to all prenatal care providers in Rochester, NY, for all their female patients of reproductive age, pregnant or not. Of 124 prenatal care providers, only 37 elected to participate, but many of these offered screening only to pregnant women. The acceptance rate among pregnant women was approximately 57%. The most common reasons for accepting screening were to obtain reassurance (50.7%) and to avoid having a child with CF (27.8 %). The most common reasons for declining screening were not intending to terminate a pregnancy for CF (32.4%) and believing that the chance of having a CF child was very low (32.2%). Compared with decliners, acceptors were more likely to have no children, regarded having a child with CF as more serious, believed themselves more susceptible to having such a child, knew more about CF, would be more likely to terminate a pregnancy if the fetus were shown to have CF, and more strongly supported offering CF screening to women of reproductive age. Of 4,879 women on whom results were obtained, 124 were found to be carriers. Of these 124 carriers, the partners of 106 were tested. Of the five at-risk couples, four requested prenatal diagnosis and one requested neonatal diagnosis. No woman found to be a carrier whose partner tested negative requested prenatal diagnosis. Except for the imperfect knowledge of those testing negative, none of the adverse outcomes predicted for CF carrier testing in the general population were observed in this study.     

Gène CFTR et infertilité masculine en 2001 Conseil génétique, diagnostic prénatal, diagnostic pré-implantatoire

As the vas deferens is also absent in the majority of CF (cystic fibrosis) males, it has been proposed that CBAVD (Congenital Bilateral Absence of Vas Deferens) males may present an incomplete or mild form of CF. Many studies using more extensive mutation analysis have confirmed the role of CFTR gene defects: 80% of CBAVD patients carry one or two mutations. Each patient with a diagnosis of CBAVD should also be examined for pulmonary and pancreatic signs, and sweat tests should be performed. In couples with CBAVD linked to CFTR mutations, the risk of having children with CF or infertility is increased if the female is also a carrier. The woman should be screened for the most frequent CFTR mutations according to her ethnic background. After screening for 80% of the mutations responsible for CF, the residual risk of being a carrier with negative screening is: Z=h(1?a)/(1?ah)=1/120 considering a carrier frequency of 1/25 in the general population. In the case of positive screening, antenatal diagnosis by chorionic villus sampling may be proposed. However, in some situations it is difficult to predict the phenotypic consequences for the child, particularly when a severe transmutation of a variable allele is identified. As these couples require medically-assisted reproduction techniques, pre-implantation genetic diagnosis appears to be more appropriate than antenatal diagnosis. Only embryos that inherit the non-mutated maternal CFTR allele are replaced in the uterus. Examination of childre born to couples with CBAVD is mandatory: immunoreactive trypsinogen assay at 3 days of age, sweat test at 3 months and clinical examination, especially looking for signs of CF. Identification of CFTR mutations in a CBAVD patient has important consequences for his family. Each sibling has a 50% risk of being a carrier and a 25% risk of inheriting the same genotype. The genetic counsellor must inform these siblings about the possible risk of having CF children if they carry CFTR mutations and if their partner is also a carrier.     

Preconception cystic fibrosis carrier couple screening: impact,understanding, and satisfaction

The impact, understanding of test-results, and satisfaction among participating couples in a preconception cystic fibrosis (CF) carrier screening project were assessed 6 months after testing. Questionnaire data were obtained from 17/18 identified carriers, 15 partners of carriers with negative test results, and 794 (73%) other participants. None of the carriers changed their reproductive plans because of their test results. Eight participants were worried about their results, including four carriers. Those who attended a general practitioner (GP) consultation for pretest education were less worried than those who attended an educational session. Seven carriers felt less healthy. Predictors of a correct understanding of test results (correct in 62% of participants) were: positive test results, high level of knowledge of CF, high level of education, attending an educational session, and previously heard of CF. All participants who reported that they were worried, all carriers, and 95% of the other participants said that they would make the same decision to be tested again. Although couples who were educated during a GP consultation were less worried, the results of the study suggest that understanding is more correct in couples attending an educational session. The results further suggest that since satisfaction with the screening was high, worries and feeling less healthy due to the test results are probably not a great burden.     

Antenatal screening for carriers of cystic fibrosis: randomised trial of stepwise v couple screening.

OBJECTIVE--To perform a rigorous comparative evaluation of stepwise and couple approaches to antenatal carrier screening for cystic fibrosis. DESIGN--Pragmatic randomised trial. SETTING--Hospital antenatal clinic serving a regional population. SUBJECTS--2002 women (couples) attending for booking antenatal visit at less than 17 weeks'' gestation with no family history of cystic fibrosis. INTERVENTIONS--Offering counselling and carrier testing for cystic fibrosis, either to women in the first instance (stepwise) or to couples (couple screening). MAIN OUTCOME MEASURES--Uptake rates; anxiety; knowledge of cystic fibrosis and carrier status (both partners); attitudes to health, pregnancy, the baby, and screening (both partners); and uptake of carrier testing by relatives. RESULTS--Uptake of screening was the same for both approaches (90%). After delivery most women remembered test results and their meaning, but 53/253 (21%) of those with negative results of couple testing had forgotten that repeat testing would be advisable if they had a pregnancy with a new partner. With stepwise screening women identified as carriers had high levels of anxiety when results were received (mean anxiety score 52.3). This dissipated with a reassuring partner''s result (carriers'' mean anxiety score 36.1) to levels similar to those receiving negative results from couple screening. Of those receiving negative results, women who had stepwise screening were significantly less anxious than those who had couple screening (mean score with result 32.1 v 35.4, 95% confidence interval for difference -4.7 to -2.1). CONCLUSIONS--Couple screening allows carriers to avoid transient high levels of anxiety, but is associated with more anxiety and false reassurance among most screenees who will test negative. Stepwise screening gives carriers and their relatives genetic information and is, in our opinion, the better method.     

Lack of interest by nonpregnant couples in population-based cystic fibrosis carrier screening.

We used signs and letters to offer free cystic fibrosis (CF) carrier screening to nonpregnant adults in stable relationships who visited numerous clinical and nonclinical sites in Nashville. A total of 179 individuals (<<1% of those eligible) elected to be tested. To understand this observation, we used questionnaires to assess individuals' attitudes about genetic testing in general and about CF carrier screening in particular (n=873). Participants expressed conflicting views about carrier screening. More than 90% of people thought that genetic testing should at least be available. Most respondents said that the views of their partners and physicians were important in their decision making, and most believed that these others favored genetic testing. Yet, more than two-thirds indicated that such factors as insurability, being "at risk," what they would need to learn, abortion, and religious beliefs were important in their decision making, opinions that mitigated against genetic testing. In particular, one-third feared that carriers would lose their health insurance, one-quarter said that they would have been more interested had they been able to provide DNA by buccal swab rather than by finger stick, and less than one-sixth believed that genetic testing was meddling in God's plan. In the face of both the low level of use of free CF carrier screening by nonpregnant couples when it was not offered in person by health-care professionals and the wide variety of concerns demonstrated, we believe that clinicians should not routinely offer carrier screening to nonpregnant individuals who do not have a family history of CF.     

Offering cystic fibrosis carrier screening to an HMO population: factors associated with utilization.

We offered cystic fibrosis (CF) carrier testing to reproductive-age enrollees in an HMO, in order to determine factors associated with test utilization in a primarily nonpregnant population. Male and female enrollees either were mailed an invitation to have the test after attending an educational session (N = 2,713) or were approached in waiting rooms at the HMO sites and given the opportunity to have the test without making an additional visit (N = 608). Uptake was considerably higher when testing could be obtained without making an additional visit (23.5%) than when attendance at an educational session was required as a prerequisite for having the test (3.7%). Utilization was higher among respondents who were planning children. Caucasians, and those with higher educational attainment. Among respondents planning to have children, individuals with higher tolerance for test uncertainty, lower fear of stigma, and higher perceived risk of being a carrier were significantly more likely to have the test. Testing decisions were not associated with the perceived burden of a child with CF or with the likelihood of aborting for CF. Although utilization of CF carrier testing is relatively low among nonpregnant individuals, uptake is significantly higher when testing can be obtained with minimal effort. Factors associated with the decision to be tested had more to do with implications of being a carrier per se than with the concerns of having a child with CF.     

Molecular screening of partners of cystic fibrosis heterozygotes.

We have screened 100 partners of known or suspected CF heterozygotes for ten CF mutations which account for 88% of the CF mutations seen by us on CF chromosomes. We have identified six CF heterozygotes amongst the 100 low-risk people screened. As two of the six people at high-risk of being CF carriers were subsequently shown not to be CF carriers this gave rise to four couples with a one in four risk of CF in a pregnancy and so far to two PND's. The risk of CF in the remaining 94 couples was reduced to less than one in 800. We have concentrated on the screening of partners for the commoner CF mutations rather than haplotyping them for the CF linked markers XV-2c/TaqI and KM19/PstI which are in linkage disequilibrium with CF. For individuals shown not to carry these ten mutations, a five fold difference in risk of being a CF carrier remains between those who have the XV-2c/KM19 genotypes associated with the highest risk(BB), as compared to those with the lowest risk(CC). Nevertheless we feel that effort is better expended in mutation screening rather than haplotyping.     

Carrier screening for cystic fibrosis among Maryland obstetricians before and after the 1997 NIH Consensus Conference

The 1997 National Institutes of Health (NIH) Consensus Conference on Cystic Fibrosis (CF) testing recommended that carrier screening be offered to all pregnant women and couples planning a pregnancy. We surveyed 492 Maryland Ob-Gyns before and after the consensus conference to: (1) assess whether obstetricians changed their practice regarding CF carrier testing, and (2) identify the factors associated with changing practice patterns, including awareness of the statement, and knowledge about CF. Fifty-six percent (275) responded to the first mail questionnaire and 107 obstetricians responded to both questionnaires. In 1998, only 18% of respondents to the second questionnaire were familiar with the NIH statement, but 43% reported discussing testing with patients with no family history, a significant increase from 1997, when only 20% reported discussing testing. Less than one-third correctly answered six multiple-choice knowledge questions about CF and carrier testing. In multivariate analysis, knowledge and familiarity with the NIH consensus statement were not associated with beginning to discuss CF carrier testing after the CF conference with their patients without a family history.     

Cystic fibrosis newborn screening: a pilot study to maximize carrier screening

Newborn screening for cystic fibrosis (CF) is expanding because early diagnosis has been shown to result in improved nutrition and growth. Most newborns identified by a mutation panel have a single detected mutation and require sweat testing to exclude an additional undetected mutation. The resulting identification of CF carrier newborns, although not the primary purpose of screening, has three potential benefits, (1) the detection of trait-trait couples, (2) presymptomatic testing of these couples' previously born children who may have undetected CF, and (3) a carrier parent alerting his/her extended family members to the chance of also being a CF carrier. Reaping each benefit requires genetic counseling of parents and their accepting carrier testing. The purpose of this study was to utilize the sweat testing visit to educate parents about the value of carrier testing for themselves and their blood relatives. We compared special care (genetic counseling after explaining the sweat test result and offering of parental DNA testing, all on the sweat test visit) versus standard care (sweat test result reported by phone to the parents the next day by the newborn's physician, ideally with the recommendation to arrange genetic counseling and parental carrier testing). In the first year of New York State CF screening, 64 newborns with one detected mutation were reported in the nine-county region that includes Rochester. Of these, parents of 39 agreed to participate in the study and to be randomized to special or standard care. Sixty-one parents completed both the initial and 1-year follow-up questionnaires (30 couples and one mother). Of the 61 parents, 23 had carrier testing after the birth of the baby. The frequency of such parental testing was significantly higher in the special care group (17/34 or 50%) than in the standard care group (6/27 or 22%) (p < 0.05). This is the first evidence from a randomized trial that genetic counseling and offering carrier testing to parents on the sweat test visit increases identification of carrier parents. Such identification detects trait-trait parents and facilitates carrier testing among relatives.     

Teaching about cystic fibrosis carrier screening by using written and video information.

We performed two studies using only written and video materials to educate people about cystic fibrosis (CF) and carrier screening. Participants were randomized to receive written or video materials. All received a brief questionnaire. Subjects in group I (n = 238) were (1) individuals in steady relationships and their partners, (2) > or = 18 years old, and (3) not pregnant. Those who accepted free screening and were not demonstrable carriers were sent a letter explaining their results and another questionnaire. Subjects in group II (n = 108) were parents seeking well child care in a university clinic. The main outcome measures were ability to answer questions correctly about (1) health status of CF carriers and people with CF, (2) the possibility of false-negative results, and (3) for those who had screening, the implications of their own results. Written and video materials were equally effective in conveying information. Prior to screening, subjects answered an average of 86% of questions correctly. Subjects with less formal education answered fewer questions correctly; 60% of those with less than a high school education had adequate knowledge of the health consequences of having CF or being a carrier, compared with > or = 94% of college graduates. Performance improved after screening. Where neither partner was a demonstrable carrier, 88% knew their own and their partner's test results, and 90% indicated that their risk of having a child with CF was not zero. Written and video educational materials can be used without face-to-face counseling to inform most people about carrier screening and their test results. These materials may be less effective for those with lower educational backgrounds.     

Cystic fibrosis heterozygote screening in 5,161 pregnant women.

A screening program for cystic fibrosis (CF) heterozygotes was conducted in a large HMO prenatal population, to evaluate the level of interest among eligible patients, the effectiveness of prescreening education, attitudes toward the screening process, psychological effects, and utilization of prenatal diagnosis and its outcomes. The heterozygote identification rate and frequency of specific CFTR mutations were also assessed. Identified carriers were offered genetic counseling and testing of male partners. Prenatal diagnosis was offered if both parents were identified as carriers. A total of 5,161 women underwent carrier testing; 947 others completed survey instruments only. The acceptance rate of screening was high (78%), and pretest education by videotape was generally effective. Adverse psychological effects were not reported. Participants generally found screening to be desirable and useful. Screening identified 142 female heterozygotes, 109 couples in which the male partner was not a carrier, and 7 high-risk couples. The incidence of R117H mutations was much higher than expected. The number of identified carriers was much lower in Hispanics than in Caucasians. We conclude that large-scale prenatal screening for CF heterozygotes in the absence of a family history of CF is an acceptable method for identifying couples at risk for affected fetuses. Sufficient pretest education can be accomplished efficiently, test insensitivity is well accepted, adverse psychological events are not observed, and general patient satisfaction is high.     

Antenatal screening for cystic fibrosis: a trial of the couple model.

OBJECTIVE--To assess the delivery and acceptability of antenatal couple screening for cystic fibrosis. Carrier status was notified only when both members of a partnership had cystic fibrosis alleles and therefore a one in four risk of having an affected child. DESIGN--Mouthwash samples were tested when both partners participated. Results were returned only to positive couples. SETTING--Two large maternity hospitals in Edinburgh. SUBJECTS--Screening was offered to all couples who booked at one of the two hospitals. MAIN OUTCOME MEASURES--(a) The take up of screening, carriers and carrier couples identified, take up of prenatal diagnosis, and numbers of affected fetuses detected; (b) questionnaire measures of patient satisfaction and stress. RESULTS--Screening was offered to 8536 couples. 714 (8.4%) were regarded as ineligible, usually because of late booking or absence of a partner. 1900 (24.3%) of the remainder declined screening. Among the 5922 screened couples, four tested positive--that is, both partners were cystic fibrosis heterozygotes. All four elected to have prenatal diagnosis. There were three terminations of pregnancy because of an affected fetus, one couple having two successive pregnancies with affected fetuses. The participation rate was 76% for eligible couples (5922/7822) and 69% for all couples (5922/8536). Only 89 screened couples (1.5%) requested information on individual carrier status. No anxiety was detected among a cohort of the screened population, and 99% of questioned participants expressed satisfaction with the concept of couple screening. CONCLUSIONS--Antenatal couple screening is a satisfactory and acceptable way of screening for cystic fibrosis and has been adopted as routine in the two trial hospitals.     

XV-2c/KM19 haplotypes analysis of cystic fibrosis patients from western Mexico

The analysis of polymorphic markers within or closely linked to the cystic fibrosis transmembrane regulator (CFTR) gene is useful as a molecular tool for carrier detection of known and unknown mutations. To establish the association between mutations in the CFTR gene in western Mexican cystic fibrosis (CF) patients, the distribution of XV2c/KM19 haplotypes was analyzed by PCR and restriction enzyme digestion in 384 chromosomes from 74 CF patients, their unaffected parents, and normal subjects. The haplotype analysis revealed that haplotype B was present in 71.9% of CF chromosomes compared to 0% of non-CF chromosomes. The F508del and G542X mutations were strongly associated with haplotype B (96.7% and 100% of chromosomes, respectively). The haplotype distribution of the CF chromosomes carrying other CFTR mutations had a more heterogeneous background. Our results show that haplotype B is associated with CFTR mutations. Therefore, haplotype analysis is a suitable alternate strategy for screening CF patients with a heterogeneous clinical picture from populations with a high molecular heterogeneity where carrier detection programs are not available. In addition, it may be a helpful diagnostic tool for genetic counseling and carrier detection in the relatives of CF patients and in couples who are planning to have children.     

Carrier screening for cystic fibrosis in a prenatal setting

Maternal prenatal cystic fibrosis (CF) screening was offered from September, 1997, to April, 1999, at the Ghent University Hospital, to couples undergoing prenatal diagnosis (amniocentesis) for reasons not related to CF. Fifteen minutes were devoted to explaining CF, CF screening, and the study protocol. The purpose was to assess the short- and long-term knowledge of CF, the attitude towards carrier screening, and carriership. A total of 314 couples entered the pilot study; 13 female CF carriers were identified. None of their partners carried an identifiable mutation. Our survey results show that information about CF and CF screening can be given effectively as part of antenatal care because most couples recalled important medical and genetic issues, valued the genetic test for CF, and seemed to cope well with the results. Risk estimates and actual numbers were more difficult to process and recall. From the small number of couples in which the woman alone was found to be a carrier, there was little or no evidence of marked distress.     

Involving consumers in the development of an educational program for cystic fibrosis carrier screening.

Input from consumers of health care was sought in developing an educational program to be provided to individuals who are considering carrier testing for cystic fibrosis (CF). In addition, we assessed the ability of health professionals to predict consumers' priorities with regard to such information. A focus group of six middle school teachers formulated questions that they would ask in trying to decide whether they wanted carrier screening for CF. Then, other adults with (n = 39) and without (n = 60) a family history of CF were presented with the questions and were asked to select the questions in the order in which they would want them answered if offered the carrier test. After each question was answered, they were asked whether they would want the carrier test if it were offered to them. CF clinic staff, clinical geneticists, and genetic counselors (n = 31) were asked to select the questions in the order in which they believed that an adult from the general population would want them answered. There were no differences in the order in which adults with and without a family history of CF would want questions answered. Consumers would want to learn about the carrier test as well as their risk of being a carrier and of having a child with CF, before receiving information on reproductive options and the effect that a child with CF would have on the family. Of the 44% of consumers who changed their mind about wanting screening during the course of selecting questions, 52% did so after the first question that they selected.(ABSTRACT TRUNCATED AT 250 WORDS)     

Carrier screening for beta-thalassemia during pregnancy in India: a 7-year evaluation

AIM: Premarital screening for beta-thalassemia is not widely acceptable in India; hence, we evaluated the effectiveness of antenatal screening and counseling over 7 years. METHODS: 61,935 pregnant women were screened using the single-tube osmotic fragility test during their first antenatal visit. Individuals who were positive were investigated further for diagnosis of beta-thalassemia and other abnormal hemoglobins. Spouses of carrier women were tested whenever available. Couples at risk were given the option of prenatal diagnosis. RESULTS: Only 19% of the women registered at the antenatal clinic in the first trimester of pregnancy, and 14% of the women were positive per the osmotic fragility test; 1020 beta-thalassemia heterozygotes and 213 women with other hemoglobinopathies were identified, majority being in the second and third trimesters. Seven hundred and thirteen (69%) of their husbands could be tested, and 37 couples at risk were identified. Only 15 couples had a prenatal diagnosis done. Four couples with affected fetuses opted for termination of pregnancy. The remaining couples either did not respond after counseling or the pregnancies were advanced for prenatal intervention. CONCLUSION: This first large study shows that antenatal screening is acceptable in India; however, awareness generation is still a primary requisite to make women register early at antenatal clinics and bring their spouses for screening when required.     

Reproductive attitudes of couples having a child with cystic fibrosis in Saguenay-Lac-Saint-Jean (Quebec, Canada)

Cystic fibrosis (CF) has a high incidence (1/936 live births) and carrier rate (1/15 inhabitants) in Saguenay-Lac-Saint-Jean. One objective of a major enquiry among several subsets of individuals from this high-risk population for CF was to evaluate the reproductive behaviour of couples with a CF child attending the comprehensive CF clinic in Chicoutimi. The knowledge of the recurrence risk resulted in deciding against further progeny or in reducing the number of children. More reliable contraception methods after the birth of the CF child, but not prenatal diagnosis, were used. Although a minority of parents with a CF child would abort a CF foetus, they apparently started viewing pregnancy interruption for CF after prenatal diagnosis as an acceptable reproductive option.     

Carrier screening for Gaucher disease in couples of mixed ethnicity

With the advent of mutational analysis for Gaucher disease, carrier screening has been incorporated into many Jewish genetic disease screening programs. Frequencies and mutations for Gaucher disease in non-Jewish populations are less well established and the detection rate of carriers are lower. Testing is problematic for resolving residual risk in a couple of mixed ethnicity. We report the testing choices made by 20 consecutive couples of mixed ethnicity where the Ashkenazi Jewish partner was identified to be a Gaucher disease gene carrier. Carrier studies of the non-Jewish partner were elected as follows: DNA studies alone, 5 (25%); enzymatic assay, 2 (10%); both, 6 (30%); no carrier studies, 7 (35%). Of the 7 couples not electing carrier studies, one was not in a pregnancy and 6 elected prenatal diagnosis in lieu of parental testing by enzymatic analysis of amniocytes. One couple elected parental carrier studies as well as prenatal diagnosis. All couples electing prenatal Gaucher determination had amniocentesis for other indications as well (4, advanced maternal age; 4, parental anxiety). We conclude that Gaucher screening is feasible for couples of mixed ethnicity if appropriate counseling and testing are offered.