Carrier screening for cystic fibrosis: a pilot study of the attitudes of pregnant women

"Suddenly Having two Positive People who are Carriers is a Whole New Thing" - Experiences of Couples Both Identified as Carriers of Cystic Fibrosis Through a Population-Based Carrier Screening Program in Australia

A population-based CF carrier screening program was implemented in Victoria, Australia in 2006. This study explored the experiences of couples when both partners were identified as CF carriers. Between January 2006 and December 2010, 10 carrier couples were identified and invited to undertake a semi-structured interview. Nine interviews were conducted, seven couple interviews and two individual interviews. One couple declined to participate due to the recent termination of an affected pregnancy. Interviews were analyzed using inductive content analysis. All couples experienced surprise on learning their carrier couple result. The couples who were pregnant at the time of screening chose to have prenatal diagnosis, with the majority considering it to be the "next step." The two couples who had an affected pregnancy reported feelings of devastation and grief upon receiving their prenatal diagnosis result and terminated the pregnancy. All carrier couples were offered free genetic counseling, with only one couple declining the offer. Couples were unprepared for a positive carrier couple result. However, all the couples changed their reproductive behavior as a result of their carrier status. The results of this study have been used to inform the program and service offered to CF carrier couples particularly with respect to genetic counseling for reproductive decision making.

Population-based carrier screening for cystic fibrosis: a systematic review of 23 years of research

Cystic fibrosis is the most common severe autosomal recessive disease, with a prevalence of 1 in 2,500-3,500 live births and a carrier frequency of 1 in 25 among Northern Europeans. Population-based carrier screening for cystic fibrosis has been possible since CFTR, the disease-causing gene, was identified in 1989. This review provides a systematic evaluation of the literature from the past 23 years on population-based carrier screening for cystic fibrosis, focusing on the following: uptake of testing; how to offer screening; attitudes, opinions, and knowledge; factors influencing decision making; and follow-up after screening. Recommendations are given for the implementation and evaluation of future carrier-screening programs.

Informing children of their newborn screening carrier result for sickle cell or cystic fibrosis: qualitative study of parents' intentions, views and support needs

Newborn screening for cystic fibrosis and sickle cell disease enables the early identification and treatment of affected children, prolonging and enhancing their quality of life. Screening, however, also identifies carriers. There are minimal or no health concerns for carriers. There are, however, potential implications when carriers reach reproductive age, and thus research attention has been given to how best to convey information about these implications in a meaningful, balanced way which does not raise undue anxieties. Most research focuses on the communication from health professional to parent, yet ultimately this information is of greatest significance to the child. This study examines parents' intentions to inform their child of newborn screening carrier results. Semi-structured interviews with 67 family members explored their intentions to inform the child, and related views and support needs. Parents almost unanimously indicated they planned to inform the child themselves. Health professionals were expected, however, to provide guidance on this process either to parents through advice and provision of written materials, or directly to the child. Although parents initially stated that they would convey the result once their child had developed the ability to understand the information, many appeared to focus on discrete life events linked to informed reproductive decision making. The results highlight ways in which health care providers may assist parents, including providing written material suitable for intergenerational communication and ensuring that cascade screening is accessible for those seeking it. Priorities for further research are identified in light of the results.

Carrier screening in preconception consultation in primary care

Discussing carrier screening during preconception consultation in primary care has a number of advantages in terms of promoting autonomy and enabling the greatest range of reproductive choices. For those with a family history of an inherited condition, this ought to be a routine discussion; however, this can be expanded to include the wider population, especially for those conditions for which carrier frequencies are considered relatively common. There is published literature from around the world regarding experiences with carrier screening in primary care for cystic fibrosis, haemoglobinopathies, fragile X syndrome, Tay-Sachs disease and spinal muscular atrophy, although many of these have tended to focus on consultations during rather than before pregnancy. Overall, these studies reveal that population carrier screening is well received by the participants with apparent minimal psychosocial harms; however, challenges exist in terms of approaches to ensure couples receive adequate information to make personally relevant decisions and for ongoing health professional engagement.

'It is not in my world': an exploration of attitudes and influences associated with cystic fibrosis carrier screening

Carrier screening for cystic fibrosis has been recommended for pregnant women and their partners, individuals and couples prior to conception, and for people with a family history. Many pilot programmes offering cystic fibrosis carrier screening, most commonly in the prenatal setting, have shown that uptake and acceptability are high. This article explores perspectives of the Victorian community regarding carrier screening for cystic fibrosis prior to offering screening. In particular whether or not such carrier screening should be offered, the best time for offering carrier screening, the information required for making a decision about carrier screening, and how this information can best be provided. A qualitative approach was taken to enable exploration of the views of stakeholders. Four focus groups and 32 interviews were conducted with a total of 68 participants. Participants were in agreement that cystic fibrosis carrier screening should be made available to everyone. However, potential consumers viewed cystic fibrosis carrier screening as 'not in my world' and were unlikely to request such screening unless it was offered by a health professional, or they had a family history. The best time for carrier screening was seen to be an individual preference and an information brochure was perceived to be useful when considering carrier screening. Lack of knowledge around the irrelevance of family history is a barrier to cystic fibrosis carrier screening. This study highlights the importance of community consultation, with stakeholders, prior to implementation of carrier screening programmes.

Factors affecting decisions to accept or decline cystic fibrosis carrier testing/screening: A theory-guided systematic review

PURPOSE

To assess factors affecting individuals' decision to accept or decline cystic fibrosis carrier testing/screening, as reported in studies published until December 2006. The Health Belief Model guided classification of each factor, and the studies' methodological quality was assessed.

METHODS

A three-stage search and retrieval process, alongside application of specific inclusion/exclusion criteria, yielded 40 studies (in 35 articles). For each reviewed study, authors abstracted and organized selected data into a matrix and assigned a methodological quality score.

RESULTS

The four most frequently identified acceptance factors included three Health Belief Model factors and one non-Health Belief Model factor: perceived benefits of undergoing cystic fibrosis carrier testing/screening, weaker perception of barriers to cystic fibrosis carrier testing/screening, fewer/no children or desiring children, and research-related factors (non-Health Belief Model factor construct). All four most frequent factors associated with declining testing were Health Belief Model factor constructs: perceived barriers to obtaining cystic fibrosis carrier testing/screening, parity, lack of knowledge, and weaker perception of benefits of undergoing cystic fibrosis carrier testing/screening. The average methodological quality of the studies was 10.2 (SD=3.2; range, 5-18 points).

CONCLUSIONS

The methodological and theoretical quality of this body of literature could be substantially improved if researchers employed theory-based approaches, tested (and reported) the validity/reliability of their own data, and employed multivariate statistical analyses and/or better controlled research designs. Improving the quality of future studies may allow better inferences regarding the relative contribution of each factor identified in this review to individuals' decision-making process.

Personal characteristics of older primary care patients who provide a buccal swab for apolipoprotein E testing and banking of genetic material: the spectrum study

OBJECTIVE

To determine the personal characteristics and reasons associated with providing a buccal swab for apolipoprotein E (APOE) genetic testing in a primary care study.

METHODS

The study sample consisted of 342 adults aged 65 years and older recruited from primary care settings.

RESULTS

In all, 88% of patients agreed to provide a DNA sample for APOE genotyping and 78% of persons providing a sample agreed to banking of the DNA. Persons aged 80 years and older and African-Americans were less likely to participate in APOE genotyping. Concern about confidentiality was the most common reason for not wanting to provide a DNA sample or to have DNA banked.

CONCLUSION

We found stronger relationships between sociodemographic variables of age and ethnicity with participation in genetic testing than we did between level of educational attainment, gender, function, cognition, and affect.

Effect of family history on disclosure patterns of cystic fibrosis carrier status

As general population screening becomes more common, an increasing number of cystic fibrosis (CF) carriers will be identified who do not have a family history of CF. Whether these carriers inform their relatives of their carrier status and whether their relatives are motivated to pursue carrier screening is unknown. We surveyed CF carriers with and without a family history of CF to understand whether and how information dissemination patterns differ, why information is or is not shared, and to what extent relatives are known to undergo testing. CF carriers were identified from a general population carrier screening clinic (group B = 18) or were parents of affected children followed at a CF clinic (group A = 30). CF carriers with a family history told essentially 100% of their living parents, siblings, and half-siblings, while those without a family history told 84% of living parents and 56% of siblings (P < 0.05). Despite the high rate of information dissemination in both groups, few siblings were known to have undergone carrier screening (14/74). Significantly fewer second- and third-degree relatives were informed about carrier status or were known to have undergone carrier screening. Group A was more likely to inform second- and third-degree relatives about carrier status. Our study documents that the frequency and reasons for disclosing CF carrier status differ between individuals with and without a family history of CF despite the fact that the reproductive risks for their relatives are the same.

Carrier screening for cystic fibrosis: a perinatal perspective

Cystic fibrosis (CF) is one of the most common autosomal recessive disorders in the United States today. One in 29 Americans, greater than 10 million people of Caucasian ethnicity, is a carrier for this genetic condition. Although it has been 10 years since the discovery of the gene for CF, carrier screening is not yet a standard of practice. The ultimate goal of carrier testing is to provide individuals at risk with information and guidance that will permit them to make informed and independent decisions. It can be anticipated that perinatal nurses will be part of the process of carrier screening of CF for prenatal patients. This article describes the nature of CF, the options for testing, and the basics of the molecular testing so nurses can be instrumental in the education process when this becomes standard practice.

Cystic fibrosis carrier population screening: a review

Population screening for cystic fibrosis (CF) carriers, now possible because of the cloning of the CFTR gene, merits evaluation because CF is common, serious, and without satisfactory treatment, and because prenatal diagnosis is available. Clinical trials of CF population carrier screening are reviewed. These trials have involved pregnant women, adults of both sexes of reproductive age, or adolescents. Schools, the usual setting for screening programs for adolescents, provide an excellent opportunity for a formal educational component and for comprehensive coverage of the population, but compared to a health-care setting, may entail subtle coercion and may compromise confidentiality. In the case of adults, many say they prefer screening before conception but do not see a physician for evaluation before conception and providers find screening more readily accomplished in the setting of a prenatal visit. Two large U.S. studies of prenatal screening with quite different subject populations and health-care settings encountered few of the adverse outcomes originally predicted for CF carrier population screening.

Prenatal tests: how are women deciding?

Women offered prenatal tests should be given sufficient information to enable them to make an informed decision. We compared the decision-making of 261 women who underwent serum screening for Down syndrome with 63 who did not. A questionnaire completed at 16 weeks' gestation assessed systematic decision-making (the weighing up of pros and cons on the basis of information presented), knowledge, anxiety and demographic information. Those undergoing screening were older but, with age partialled out, they had more knowledge about the test and made decisions less systematically than those not screened.

Predictive testing for Huntington's disease: I. Predictors of uptake in South Wales

In Wales, predictive testing for Huntington's disease (HD) has not been offered proactively to families and uptake of testing is low in comparison to other centres. Little is known of those not requesting testing, particularly those not in direct contact with the genetics service. This study examined differences between a cohort of 22 test applicants and a random group of 32 'non-requesters', drawn from the South Wales HD register. Respondents were interviewed by means of a semi-structured schedule in their own homes. The study groups differed significantly on a number of variables including: knowledge of the availability of testing; perceived attitudes of family members and significant others to testing; length of knowledge and perceived stressfulness of being at risk; and perceived ability to cope with an unfavourable result. Overall, knowledge of testing procedures was poor and at-risk individuals' understanding of genetic terminology was at odds with scientific distinctions. Discussion focuses on the organisational and psychological factors associated with lack of knowledge of the availability of testing and the interpretation of reported coping capacities.

Costs, effects, and savings of screening for cystic fibrosis gene carriers

STUDY OBJECTIVE

Evaluating the costs, effects, and savings of several strategies for cystic fibrosis (CF) gene carrier screening.

DESIGN

A general model for evaluating prenatal, preconceptional, school, and neonatal carrier screening was constructed. For prenatal and preconceptional screening, two strategies were evaluated: single entry and double entry two step couple screening. Firstly, the Dutch situation was evaluated prospectively; subsequently the results were generalised to other carrier frequencies.

SETTING

Prospective simulation model.

MAIN RESULTS

Of all screening strategies, neonatal carrier screening gives most carrier couples an informed choice concerning reproduction. If the parents of carrier newborns would not be tested however, prenatal screening detects most carrier couples. Prenatal and single entry preconceptional screening programmes have a favourable cost-savings balance in the Netherlands under a wide range of assumptions. For double entry preconceptional screening and neonatal screening, high enough values of uptake of screening, prenatal diagnosis, and induced abortion are necessary. School carrier screening does not have a favourable cost-savings balance.

CONCLUSIONS

If a CF screening programme is judged to be useful on individual and social grounds, costs considerations are no obstacle for prenatal and single entry preconceptional screening.

Carrier screening for cystic fibrosis: costs and clinical outcomes

OBJECTIVES

To evaluate the costs and clinical effects of 16 alternative strategies for cystic fibrosis (CF) carrier screening in the reproductive setting; and to test the sensitivity of the results to assumptions about cost and detection rate, stakeholder perspective, DNA test specificity, chance of nonpaternity, and couples' reproductive plans.

METHOD

Cost-effectiveness analysis.

RESULTS

A sequential screening strategy had the lowest cost per CF birth avoided. In this strategy, the first partner was screened with a standard test that identifies 85% of carriers. The second partner was screened with an expanded test if the first partner's screen was positive. This strategy identified 75% of anticipated CF births at a cost of $367,000 each. This figure does not include the lifetime medical costs of caring for a patient with CF, and it assumes that couples who identify a pregnancy at risk will choose to have prenatal diagnosis and termination of affected pregnancies. The cost per CF birth identified is approximately half this figure when couples plan two children.

CONCLUSIONS

The cost-effectiveness of CF carrier screening depends greatly on couples' reproductive plans. CF carrier screening is most cost-effective when it is performed sequentially, when the information is used for more than one pregnancy, and when the intention of the couple is to identify and terminate affected pregnancies. These conclusions are important for policy considerations regarding population-based screening for CF, and may also have important implications for screening for less common diseases.

Carrier screening for cystic fibrosis: test acceptance and one year follow-up

We identified 124 carriers among 4,879 patients of prenatal care providers in the Rochester region. Six factors were identified that together permitted a correct classification regarding test acceptance for 77.5% of all subjects. For those pregnant, the most influential of these factors was a more accepting attitude toward abortion. As an indication for abortion, cystic fibrosis (CF) ranked between mild and moderate mental retardation. Of the 124 carrier women identified, we obtained 1-year follow-up information on 100. Mean score for CF knowledge at 1 year (77.4 +/- 13.2%), although significantly lower than immediately after counseling (84 +/- 12.4%), was still significantly higher than after detection but before counseling (51.1% +/- 20.7%). Anxiety about having a child with CF significantly declined from 25.8 +/- 8.0 SD immediately after counseling to 18.9 +/- 7.8 at 1 year (Spielberger State Anxiety Scale). Although 15 carriers regretted having been tested, 83% believed that they benefited from testing, 83% would make the same decision to be tested over again, and 79% would recommend testing to a friend. We conclude that, for most women, CF carrier screening accomplished its purpose: most carriers detected came for counseling, had their partners tested, and, if their partners were also carriers, had prenatal diagnosis. The major undesirable outcomes were that many women testing negative did not understand that a negative result did not exclude being a carrier and that three women found to be carriers did not have their partners tested because of anxiety or the unacceptability of pregnancy termination and therefore may not have carefully considered their decision to be tested. Both of these undesirable outcomes could have been avoided by greater attention to pretest patient education by the primary care provider.

Economic evaluation of prenatal diagnosis: a methodological review

This paper discusses the role of economic evaluation in prenatal diagnosis. As the availability of new and improved techniques of prenatal diagnosis increases, so does the relevance of economic evaluation. The various methods of economic evaluation are discussed in the context of amniocentesis and chorionic villus sampling. It is argued that in view of the potentially wide range of benefits from prenatal diagnosis, more sophisticated measures of benefit should be incorporated into economic evaluations. Further development of utility-based measures and monetary valuation is suggested.

Evaluating the benefits of antenatal screening: an alternative approach

This paper presents an alternative method of valuing the benefits of antenatal screening programmes based on individual preferences. The methods of benefit measurement used to date, namely averted costs, QALYs, and willingness to pay, are critically reviewed. The alternative method assumes that screening can be regarded as an investment in improved information, and that the benefits of screening can be measured by the value placed upon this information. The information is valued by presenting individuals with standard gamble questions framed in terms of a prenatal diagnostic choice. The approach is developed in the context of antenatal screening for Down's syndrome and for cystic fibrosis carrier status. Some empirical testing of the approach is reported for the latter.

Genetic screening for reproductive planning: methodological and conceptual issues in policy analysis

OBJECTIVES

This paper explores several critical assumptions and methodological issues arising in cost-effectiveness analyses of genetic screening strategies in the reproductive setting.

METHODS

Seven issues that arose in the development of a decision analysis of alternative strategies for cystic fibrosis carrier screening are discussed. Each of these issues required a choice in technique.

RESULTS

The presentations of these analyses frequently mask underlying assumptions and methodological choices. Often there is no best choice. In the case of genetic screening in the reproductive setting, these underlying issues often touch on deeply felt human values.

CONCLUSIONS

Space limitations for published papers often preclude explaining such choices in detail; yet these decisions determine the way the results should be interpreted. Those who develop these analyses need to make sure that the implications of important assumptions are understood by the clinicians who will use them. At the same time, clinicians need to enhance their understanding of what these models truly mean and how they address underlying clinical, ethical, and economic issues.

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.

Decision making with respect to diagnostic testing: a method of valuing the benefits of antenatal screening

This paper outlines a model for valuing the benefits of antenatal screening based on the analysis of individual decision making with respect to consequent diagnostic testing. Central to the model is the idea that the benefits of screening can be measured by valuing the improved information generated from screening. The model is developed in the context of antenatal carrier screening for cystic fibrosis (CF). Benefits are assessed by surveying women in the general population in order to establish their preferences for two alternative methods of CF carrier screening-stepwise and couple screening. Preferences are elicited using standard-gamble questions in which women from a population-based random sample are asked to trade off risk of fetal loss with improved information from diagnostic testing. A series of standard-gamble questions is employed to elicit utility values for each of the possible information outcomes from screening. The expected utilities of both screening methods are calculated at both individual and group levels. The results suggest that the use of individual decision making with respect to diagnostic testing as a means of valuing the benefits of screening may have wide applications.

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.

Willingness to pay for antenatal carrier screening for cystic fibrosis

We report on a study of women's willingness to pay (WTP) for a cystic fibrosis carrier test by one or other method of service delivery (disclosure or non-disclosure). The results demonstrate that there was no statistically significant difference in WTP for the methods of testing. Those women who received a negative test result were followed up and asked their WTP for such a result. Values obtained at this stage were 16 per cent higher than those obtained pretest result. Use of prompts, rather than simply asking women to state their WTP, had a statistically significant effect on post-test result values. The opportunity to terminate the pregnancy, if a test proved positive, was important, but was not the only consideration. This demonstrates the importance to women of other benefits of screening.

Barriers to carrier testing for adult cystic fibrosis sibs: the importance of not knowing

Early experience in centers offering population screening for cystic fibrosis (CF) has shown that few of the public are taking advantage of the offer [Miller, 1993: New Scientist 139:6]. There is similar low utilization among adult CF sibs [Fanos and Johnson, 1993: Am J Hum Genet 53:A51]. The purpose of this study was to identify factors motivating or interfering with the pursuit of carrier testing in adult CF sibs. Eighty-four adult CF sibs and their spouses, drawn from Children's Hospital, Oakland, CA, and Children's Hospital, Boston, MA, were interviewed for about an hour, and qualitative material was coded on various themes. Structural and psychological barriers to the transmission of genetic information were identified: 1) sibs encountered difficulty in obtaining information concerning availability of testing; 2) parental guilt and blame prevents parents from discussing genetic issues with the sib; 3) sibs rarely discuss testing with each other; 4) the CF patient or parent often has difficulty with the implications of the sib seeking carrier testing; 5) family and individual myths about carrier status influence the sib's decision to seek testing; 6) statistical odds have lost meaning in families where the rare has already occurred; 7) the sib fears loss of interpersonal desirability; and 8) carrier status can serve an important function in binding guilt. Remaining unaware of their carrier status may serve significant psychological functions for individuals at risk.

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.

Genetics, ethics, and Alzheimer disease

This article considers the emerging research on Alzheimer disease (AD) genetics in relation to ethical questions surrounding presymptomatic and prenatal genetic testing. Given the rapid advance in AD genetics over the past 8 years, it is likely that the attention of clinicians and ethicists will increasingly turn to genetic issues. After a survey of current genetic knowledge, this article addresses 3 areas of likely ethical concern. While AD genetic screening programs are currently rare and restricted to specific pedigrees, they will become more common in the future. It is, therefore, imperative that society and clinicians begin to consider the ethical issues this raises.

Patient and parental attitudes toward genetic screening and its implications at an adult cystic fibrosis centre

General population screening for cystic fibrosis carrier status in the United Kingdom would detect 72% of at-risk couples. Proper counselling would allow these couples to make informed reproductive choices, including the possibility of prenatal diagnosis and the termination of an affected pregnancy. However, children with cystic fibrosis born in this decade, given optimum treatment, now have an average life expectancy of 40 years, and there is no unanimity of opinion on how, where, when, or even if, screening should be offered. The purpose of this questionnaire-based study was to examine the attitudes of an adult clinic population who have grown up with cystic fibrosis, and of their parents, towards genetic screening programmes and the controversies and ethical dilemmas surrounding such programmes in cystic fibrosis. Both patients and parents supported prenatal screening (88% and 90%) and the option of terminating an affected pregnancy (68% and 84%). Only 22% of patients and 10% of parents felt that screening should be limited to families with a history of cystic fibrosis, and 19% and 6%, respectively, that prenatal diagnosis should be restricted to those with a previous child with cystic fibrosis. Despite the negative aspects of any screening programme and the acknowledged ethical problems peculiar to cystic fibrosis, the conclusion of our patients and parents who have lived intimately with the illness is that there should be the option of utilising information available from genetic screening for cystic fibrosis to guide reproductive choices. Pilot programmes to define the optimum management of such screening should continue.

Cost-benefit analysis of a national screening programme for cystic fibrosis in an Israeli population

The recently acquired ability to identify 97% of CF carriers in an Israeli Ashkenazi population, prompts an evaluation of a nationwide screening programme. In 1993, the programme would first screen and counsel 9,261 parents, then 396 spouses of carrier parents and finally screen 16.5 fetuses where both parents are carriers. Assuming 92% of screened parents choose abortion of fetus screened positive, 2.33 cases of CF will be prevented in 1993 at a direct cost of $781,000. The $326,000 direct costs of preventing a CF case, exceed the lifetime excess direct costs per case of $297,000. However, benefits of screening also accrue to subsequent pregnancies, resulting in a direct benefit ($14.45 million) to cost ($10.39 million) ratio of 1.39/1 for the period 1993-2032. When benefits and costs resulting from mortality changes, work absences and transport costs are included, the benefit ($15.95 million) to cost ($13.88 million) ratio falls to 1.15/1. Benefit-cost ratios are lower for other ethnic groups in Israel, due to lower carrier rates and lower mutation detection abilities. A CF screening programme will increase the freedom of individuals choice, but should be carried out carefully in order to minimize stigmatization and even discrimination against CF carriers.

Prenatal diagnosis and a donor splice site mutation in fibrillin in a family with Marfan syndrome

The Marfan syndrome, an autosomal dominant connective tissue disorder, is manifested by abnormalities in the cardiovascular, skeletal, and ocular systems. Recently, fibrillin, an elastin-associated microfibrillar glycoprotein, has been linked to the Marfan syndrome, and fibrillin mutations in affected individuals have been documented. In this study, genetic linkage analysis with fibrillin specific markers was used to establish the prenatal diagnosis in an 11-wk-gestation fetus in a four-generation Marfan kindred. At birth, skeletal changes suggestive of the Marfan syndrome were observed. Reverse transcription-PCR amplification of the fibrillin gene mRNA detected a deletion of 123 bp in one allele in affected relatives. This deletion corresponds to an exon encoding an epidermal growth factor-like motif. Examination of genomic DNA showed a G-->C transversion at the +1 consensus donor splice site.

What young people think and do when the option for cystic fibrosis carrier testing is available

We report findings in phase II of a pilot study of cystic fibrosis (CF) carrier screening/testing by mutation analysis. Phase I has been reported elsewhere. Eligible participants in phase II (n = 815) were students (15 to 17 years of age) in public high schools. An educational component (exchange of information and discussion about common genetic disorders including CF) preceded, by one week or more, voluntary participation in the screening component which required a blood sample. The uptake rate for screening was 42%. Nine carriers (2pq = 0.0260) were identified, all with the delta F508 mutation; students were also tested for G551D, G542X, W1282X, and -549-mutations, but no carriers of these alleles were found. Carriers had positive views of the education and testing experiences. Persons identified as 'non-carriers' were also surveyed (n = 135, response rate 41%). As in phase I, the majority (83%) again understood that a negative DNA test had not excluded them from possible carrier status. Students who participated in the informational component but were not screened served here as controls in the follow up survey (n = 208, response rate 53%). Their views were similar to those of the screened non-carriers, and similar also to those held by students, adults, pregnant women, couples, and CF relatives in other communities.

Sometimes sensitive, seldom specific: a review of the economics of screening

As the policy relevance of screening has increased, the application of the techniques of economic evaluation to screening has become widespread. This paper critically reviews the literature, and in so doing, highlights several ways in which future evaluations might be improved. These include: the adoption of a broader perspective regarding the questions to be addressed and the relevant margins; a reconsideration of the nature of the benefits and how they might be valued; and a greater emphasis being placed upon the role of individual behaviour and its potential impact on the outcome of economic evaluations.