Intended use of predictive testing by those at risk for Huntington disease

Huntington disease (HD) is a late-onset genetic disorder that is incurable and undetectable until the onset of symptoms. A marker for the gene that causes HD was recently discovered that will lead to a predictive test. The purpose of this research was to assess the attitudes, beliefs, and behavioral intentions concerning the impending predictive test by those at risk for HD. Results from a sample of 56 at-risk individuals indicated that a majority (65%) favored using the presymptomatic test and would encourage their adult children to use it as well. Fewer but still a substantial percentage of respondents would use the prenatal test (42%) and would test at-risk minors (35%). Surprisingly, knowledge about predictive testing was quite low and a majority of those least knowledgeable about predictive testing intended to use the test. These findings emphasized the need for outreach and prevention efforts to prepare the at risk and specialized programs of genetic counseling and follow up to accompany predictive testing.     

Attitudes of persons at risk for Huntington disease toward predictive testing

Attitudes of 69 persons at risk for Huntington disease (HD) were obtained by means of semistructured interviews and questionnaires. About 79% of the individuals said that they would use a presymptomatic predictive test if it were available. All believed that the test should be made available even though there was no cure for HD. Nearly 2/3 of subjects would use the test for prenatal diagnosis, and of these 71% would terminate a pregnancy if the fetus was found to carry the HD gene. Most subjects believed that pretest counseling should be mandatory and many said that testing should be withheld from persons who were psychologically unstable or were threatening self-harm. The data suggest that about 2-6% of persons at risk for HD may have severe psychiatric or suicidal responses to a positive outcome of predictive testing. This underscores the need for adequate pretest counseling and the availability of professional and community resources to deal with the impact of predictive testing on individuals and their relatives.     

At-risk persons' attitudes toward presymptomatic and prenatal testing of Huntington disease in Michigan

One hundred fifty-five individuals at 50% risk of inheriting Huntington disease (HD) were given a questionnaire surveying their sociodemographic characteristics, experience with HD, and attitudes toward presymptomatic and prenatal testing in HD. About two-thirds (63.2%) of the persons indicated they would take a presymptomatic test even if no specific treatment was available. Although one-half (49%) of the respondents stated they would make use of a prenatal test, only 43% of these individuals would decide to terminate a heterozygous fetus. Presymptomatic test results indicating carrier status would influence some of the respondents' decisions about marriage and childbearing. This strong interest of at-risk persons to make use of both presymptomatic and prenatal diagnosis in HD indicates the need for well-organized testing programs. These programs must be designed to address the genetic, psychosocial, and ethical issues that may arise in the use of this type of genetic test.     

Reluctance to undergo predictive testing: The case of Huntington Disease

The development of a presymptomatic test for Huntington Disease (HD) has enabled some persons at risk to determine whether or not they are gene carriers. The purpose of this study was to explore the reasons why those at risk choose not to be tested in a situation where testing is available and most of the test-associated costs are covered by state funding. Subjects were also asked their levels of knowledge about testing, attitudes towards aspects of the testing protocols, and intentions towards testing once the gene for HD is found. Sixty-six individuals at risk for HD who had chosen not to be tested completed a mailed questionnaire. The most important reasons for not being tested were increased risk to children if one was found to be a gene carrier, absence of an effective cure, potential loss of health insurance, financial costs of testing, and the inability to “unndo” the knowledge. Individuals comprising this sample were quite knowledgeable about predictive testing. Most supported the availability of testing despite the lack of a cure, the need for special counseling prior to testing, and the idea that testing should be a voluntary decision. Most said they would take the test if a treatment was available, if the mechanics of the test were simplified, or if the test was 100% accurate. The risk to relatives, lack of treatment or cure, fear of losing one's health insurance, and the accuracy of the information to be gained from testing are important factors in the decision not to be tested. © 1993 Wiley-Liss, Inc.     

Understanding the decision to take the predictive test for Huntington disease.

The predictive test for Huntington disease (HD) has allowed those at risk to determine gene status prior to symptoms. The purpose of this research was to understand the motivation and the anticipated reactions of those requesting the test. Forty persons at 50% risk for HD and 31 companions participated in a structured personal interview as part of the predictive test protocol. Reasons for taking the test centered on the reduction of anxiety and uncertainty associated with being at risk and enhanced planning and decision making. Participants also believed that taking the test would produce more positive than negative outcomes. With a favorable result, most anticipated a reduction of anxiety, a more normal future, and relief knowing their children would be at a very low risk. Most also cited benefits as more likely than consequences with an unfavorable result. Making the most of life, easier planning, and reduced uncertainty were rated as more likely than any of the adverse impacts, including short-term depression and becoming frightened. Almost all participants (95%) said they would rather learn that they have the HD gene than remain at 50% risk. The uncertainty, anxiety, and chronic stress associated with being at risk appears to underlie the motivation of many seeking the predictive test for HD.     

Understanding the decision to take the predictive test for Huntington disease

The predictive test for Huntington disease (HD) has allowed those at risk to determine gene status prior to symptoms. The purpose of this research was to understand the motivation and the anticipated reactions of those requesting the test. Forty persons at 50% risk for HD and 31 companions participated in a structured personal interview as part of the predictive test protocol. Reasons for taking the test centered on the reduction of anxiety and uncertainty associated with being at risk and enhanced planning and decision making. Participants also believed that taking the test would produce more positive than negative outcomes. With a favorable result, most anticipated a reduction of anxiety, a more normal future, and relief knowing their children would be at a very low risk. Most also cited benefits as more likely than consequences with an unfavorable result. Making the most of life, easier planning, and reduced uncertainty were rated as more likely than any of the adverse impacts, including short-term depression and becoming frightened. Almost all participants (95%) said they would rather learn that they have the HD gene than remain at 50% risk. The uncertainty, anxiety, and chronic stress associated with being at risk appears to underlie the motivation of many seeking the predictive test for HD.     

Attitudes towards cancer predictive testing and transmission of information to the family.

Before the organisation of breast cancer predictive testing in France, consultands' attitudes towards this kind of testing and towards passing on information about the family cancer risk to their relatives were investigated. This survey was carried out from January 1994 to January 1995 at six specialised cancer genetic clinics located in different parts of France Female consultands who were first degree relatives of cancer patients and who had at least one case of breast cancer in their family, affecting either themselves or a first degree relative or both, participated in this study. Among the 248 eligible consultands attending the clinics during the study period, 84.3% answered a post-consultation questionnaire. Among the 209 respondents, 40.7% (n = 85) were cancer patients and 59.3% (n = 124) were healthy consultands. A high consensus in favour of genetic testing was noted, since 87.7% of the sample stated that they would ask for breast cancer gene testing if this test became available. The underlying assumption of 96.6% of the women was that their health surveillance would be improved after a positive test. A high awareness of the anxiety that would be generated in a family after a positive result was observed and found to be associated (p < 0.05) with the anxiety and depressive profiles of the patients. Half of the healthy respondents said they would not change their attitude towards screening if the results of predictive testing turned out to be negative. Only 13.7% of the 161 patients who stated that the oncogeneticists asked them to contact their relatives firmly refused to do so, mainly because of difficult family relationships.     

Attitudes toward presymptomatic testing in Huntington disease

One hundred thirty-one individuals at 50% risk of inheriting Huntington disease (HD) responded to a survey to study their attitudes toward taking a genetic test based on the identification of a genetically linked DNA polymorphism. Ninety-six percent of the respondents believe that presymptomatic testing should be available, and 66% say they will use it themselves. Fewer married individuals, in comparison to those single, separated, and divorced, intend to take the test. Many respondents (40%) said their primary reason for wanting to be tested is to end the uncertainty in their lives. Results suggest that there will be self-selection in test use, with many individuals who believe they will be depressed or possibly suicidal with a positive test result deciding not to be tested or unsure about testing. However, 15% of those who want to be tested acknowledge that they may be at risk for suicide if they are probable gene carriers. Only 12% of all respondents say they will be likely to use prenatal testing, suggesting that initial demand may be low in New England. Implementation of presymptomatic testing challenges health care providers to develop strategies to care for otherwise healthy persons who will be given a diagnosis years before the onset of illness.     

Personal theories of inheritance,coping strategies,risk perception and engagement in hereditary non-polyposis colon cancer families offered genetic testing

From the geneticist's (or 'genetic counsellor's') perspective, lay models of inheritance can be perceived as problematic because they might interfere with understanding and acceptance of the explanation of inheritance provided in genetic counselling. The work presented here forms part of a larger qualitative grounded-theory study where the aim was to develop theory that could explain variations in adjustment to genetic testing for hereditary non-polyposis colon cancer (HNPCC). Ten of the 29 individuals interviewed who were at 50% or 25% risk used a 'personal theory of inheritance' to justify or explain a belief that they did, or did not, carry the family mutation. Two others indicated that, as a coping strategy, they chose to believe themselves to be carriers. This article presents part of the theory of engagement that was constructed using this data, relating to the process of development of risk perception. The theory suggests that for some individuals, these beliefs can form part of a process of coping and coming to terms with risk. An exploration of these processes may help practitioners to better understand the complexity of risk perception in individuals at genetic risk for cancer, particularly those preparing for predictive test results. Further development and testing of the theory is discussed.     

On attitudes and appreciation 6 months after predictive DNA testing for huntington disease in the Dutch program

We have studied the 6-month follow-up attitudes of 63 individuals, after predictive testing for Huntington disease (HD). Reducing uncertainty (81%) and family planning (60%) were the major reasons for taking the test. Twenty-four individuals were diagnosed as having an increased risk (± 98%), and 39 a decreased risk (± 2%). Among those with an increased risk, denial or minimization of the ultimate impact of the increased risk result was observed. Most of them (84%) rated their current life situation, at the very least, as being good. Twenty-one percent of individuals with an increased risk who originally planned to have a family, decided to refrain from having children. Sixty percent of those with increased risk who still wished to have children, would choose to have prenatal testing. In most individuals with increased risk, the test result did not increase the previously expected control over their own future. Half of the partners of persons with increased risk acknowledged the burden of the future disease. Half had no one in whom they could confide. They showed loyalty to the denial and avoidance reactions of their spouses. Half of the individuals with decreased risk denied the impact of the result, as reflected by absence of relief, and emotional numbness. A third of persons with decreased risk experienced involvement with problems of affected relatives. We found that 20% of all participants were discontented with the support given by their general practitioner, who is normally regarded as being the most significant professional for aftercare. Our findings suggest that the perpetuation of psychological defenses, which may temporarily be adequate, may ultimately prevent an individual from taking advantage of being informed. These questions should be further addressed in long-term follow-up studies. © 1993 Wiley-Liss, Inc.     

Problems assessing uptake of Huntington disease predictive testing and a proposed solution

The uptake of predictive testing for Huntington disease informs our understanding of decision making by those at risk and assists with planning for service provision. Uptake figures have been reported from several centers based on the total number of people who have undertaken predictive testing as a percentage of those estimated to be at 50% risk in the region. This method produced a figure of 35% from our own service, much higher than observation of the local pedigrees indicated, and higher than other published reports. We have identified some errors in the commonly used formula. The major errors are the use of the cumulative total of those who have had testing with a static denominator of those at 50% risk, and the failure to exclude from the at-risk group those who are too young and therefore ineligible to test.We report data from the Huntington Disease Register of Victoria and estimate the prevalence to be 8 per 100,000 in 1999. Additional data on individuals at risk were collated. We found that for every diagnosed person there were 4.2 individuals at 50% risk, a lower ratio than one to five hypothesized in the literature. We examined these ratios in the context of uptake.Significantly, we provide a solution to the calculation of uptake with a formula that factors in a dynamic denominator and corrects for the number of years testing has been offered. Using this formula, we calculated an uptake of 13.0-15.4% for the state of Victoria, Australia. This formula can be used to compare uptake across different centers.     

Attitudes to predictive DNA testing in familial adenomatous polyposis.

Attitudes to predictive DNA testing for familial adenomatous polyposis were documented in 62 affected adults. Patient views on prenatal testing and termination of pregnancy for this disorder were sought, as were opinions on the most suitable age to offer predictive testing for at risk children and the most appropriate age to begin screening. While 15 (24%) of those questioned stated that they would proceed to termination of pregnancy if a prenatal test indicated that the unborn baby was affected, in clinical practice no one has yet requested this option. Six (10%) people who had refrained from having children for fear of passing on the polyposis gene felt that the arrival of prenatal testing would enable them to consider planning a family. The majority of patients (93%) said they would like their children tested by DNA analysis at birth or in infancy, but felt that 10 to 12 years was the most appropriate time to discuss the diagnosis with the child.     

Interest in genetic testing among first-degree relatives of breast cancer patients

The recent cloning of a breast-ovarian cancer susceptibility gene (BRCA1), and determination of the locus of a related gene (BRCA2), offers potential for clinical genetic testing for breast cancer susceptibility. This study examined interest in and expectations about an impending genetic test among first-degree relatives (FDRs) of breast cancer patients. One hundred five females completed two structured telephone interviews to assess demographics, breast cancer risk factors, psychological factors, and attitudes about genetic testing for breast cancer susceptibility. Overall, 91% of FDRs said that they would want to be tested, 4% said they would not, and 5% were uncertain. The most commonly cited reasons for wanting genetic testing were to learn about one's children's risk, to increase use of cancer screening tests, and to take better care of oneself. Women with less formal education were motivated by childbearing decisions and future planning to a greater degree than were women with education beyond high school. Most women anticipated a negative psychological impact of positive test results, involving increased anxiety (83%), depression (80%), and impaired quality of life (46%). In addition, 72% of women indicated that they would still worry if they tested negative. In multivariate regression analysis, level of baseline depression was the strongest predictor of an anticipated negative impact of genetic testing (Beta =.15; P,.0001). These results suggest that the demand for genetic testing for breast cancer susceptibility may be great, even among women who are not likely to have predisposing mutations. Prior to widespread availability of such testing, it will be critical to develop informed consent protocols to educate individuals about the benefits and limitations of predictive testing for this multifactorial disease. © 1995 Wiley-Liss, Inc.     

Presymptomatic DNA testing for Huntington disease: Identifying the need for psychological intervention

In the Dutch presymptomatic DNA-testing program for Huntington disease (HD), 29 individuals with increased risk and 44 with decreased risk were followed-up 6 months after test results. A prognostic model was built aimed at identifying individuals at risk for psychological maladjustment, as measured by the Impact of Event Scale, the Beck Hopelessness Scale, the General Health Questionnaire, and the Social Support Questionnaire. Results: 1) The more that applicants suffered from intrusive feelings about HD and tried to avoid HD-related situations, prior to the test, the greater the chance that they will experience this 6 months after the test if they proved to be at increased risk; 2) the more that both individuals with increased risk and those with decreased risk who suffered from the threat of having HD tried to avoid HD-related situations prior to the test and the less satisfied they were with available support, the greater the probability that they will show avoidance behavior after the test; 3) the more pessimistic that individuals with increased risk as well as those with decreased risk were about their future prior to the test, the more they avoided HD-related situations and the more dissatisfied they were about their available support (pretest), the greater the probability that they will become depressive and suicidal. Psychological adjustment was also studied as a function of a) intrusion/denialavoidance pattern over time and b) healthy mental functioning/future expectancies. Most individuals with increased risk (86%) seem to cope well thus far, although this was based largely on strong psychological defenses and dependent on satisfactory relationships. Five individuals with increased risk (17%) had either health complaints and/or extreme pessimistic expectancies. They were not able to face the consequences of the test result and showed an increase of denial-avoidance behavior thereafter. Seven out of 9 individuals with decreased risk, identified as possible psychopathological cases with pessimistic expectancies, had less intrusive feelings than prior to the test. This group could later develop severe problems with detachment from their previous life style and also with adapting to their new genetic status. We conclude that DNA-testing has shown benefits for most tested individuals. However, a considerable number are at risk for maladjustment and should be offered additional help. Further studies as to whether the strong defenses in individuals with increased risk safeguard adequate adjustment in the long term should be undertaken. © 1993 Wiley-Liss, Inc.     

Psychosocial impact of predictive testing for myotonic dystrophy type 1

In the Saguenay-Lac-Saint-Jean region (Quebec, Canada), a predictive DNA-testing program for myotonic dystrophy type 1 (DM1) has been available as a clinical service since 1988. From 1 to 12 years (median, 5 years) after receiving predictive testing, a total of 308 participants (44 carriers and 264 non-carriers) answered a questionnaire to determine the psychosocial impact of this genetic testing. The main reasons for wanting to be tested were to learn if children are at risk for DM1 or for reproductive decision making (75%) and to relieve the uncertainty for themselves (17%). The majority of participants (96.1%) remembered correctly their test result. At the time of the survey, the perception of the general well-being, the psychological distress (Psychiatric Symptom Index), and the self-esteem (Rosenberg Self-Esteem Scale) were similar in carriers, in non-carriers, and in the reference (Quebec) population. When participants indicated a change in different aspects of their lives following predictive testing, it was perceived as a change for the better by non-carriers and as a change for the worse by carriers. Nevertheless, for a majority of carriers and of non-carriers, the test result did not bring changes in their lives. All respondents believed that predictive testing should be available for the at-risk population and the vast majority of carrier and of non-carriers would recommend the use of predictive testing to their family members. Predictive testing for individuals at-risk of DM1 can be offered safely within a well-organized clinical and genetic counseling program that includes careful pre-test counseling, pre-test clinical assessment, post-test psychological support, and follow-up for those identified as carriers.     

Objective knowledge about Huntington''s disease and attitudes towards predictive tests of persons at risk.

The task of genetic counselling of people at risk for Huntington's disease might be facilitated by increased knowledge of relevant population characteristics. The aim of the present study was to clarify select socioeconomic characteristics, knowledge concerning the disease, and attitudes towards predictive tests of people at 50% risk of inheriting Huntington's disease in the state of Victoria. A random sample of subjects was drawn from the Huntington's disease register and 50 questionnaires were analysed. Respondents completed three questionnaires which covered their socioeconomic characteristics, the extent and accuracy of their knowledge about the genetic, progress, and treatment of Huntington's disease, and their attitude and acceptance of predictive tests as well as their intentions about future reproduction. A very positive attitude was found to be held by the respondents towards a predictive test if it was safe, reliable, and non-invasive. Resultant problems which would arise, should a reliable test be found, are discussed. The respondent's knowledge concerning the disease was found to be adequate generally.     

Five year study of prenatal testing for Huntington''s disease: demand, attitudes, and psychological assessment.

Adult predictive and prenatal testing programmes for Huntington's disease (HD) in Canada have been available since 1986. However, the demand for prenatal testing and the reasons why some people choose not to have the prenatal test for this late onset disorder have not been well documented. In addition, the knowledge and attitudes of adult predictive testing candidates and their partners about prenatal testing are not well known nor are the psychological effects of prenatal testing well understood. As of September 1991, 425 subjects had entered the Canadian Collaborative Study of Predictive Testing and, of these, 47 subjects or their partners had become pregnant. Of this group, 14 (30%) couples requested prenatal testing, 24 (51%) couples did not want prenatal testing, and nine (19%) at risk subjects had already received a decreased risk through adult predictive testing and, therefore, were not eligible for the prenatal test. Of the 14 couples who initially requested prenatal testing, seven withdrew. Thus, demand for the prenatal test by eligible candidates was 7/38 or 18%, which is much lower than the 32 to 65% expected based on early survey data. The most frequently cited reason for declining prenatal testing was the hope that a cure would be found in time for their children. While the majority of adult predictive testing candidates (71%) in our study had accurate information about definitive prenatal testing, many (63%) did not have a correct understanding of exclusion prenatal testing. Although no serious adverse events such as suicide planning or admission to psychiatric hospital have occurred, a particular need for careful counselling was identified for those at risk candidates and their partners who have one prenatal test and feel compelled to use the test again in future pregnancies. Even though prenatal testing for HD is not requested as often originally expected, it still remains a desired option for some at risk persons and their partners.     

Predictive,pre-natal and diagnostic genetic testing for Huntington's disease: the experience in Canada from 1987 to 2000

Predictive and pre-natal testing for Huntington's Disease (HD) has been available since 1987. Initially this was offered by linkage analysis, which was surpassed by the advent of the direct mutation test for HD in 1993. Direct mutation analysis provided an accurate test that not only enhanced predictive and pre-natal testing, but also permitted the diagnostic testing of symptomatic individuals. The objective of this study was to investigate the uptake, utilization, and outcome of predictive, pre-natal and diagnostic testing in Canada from 1987 to April 1, 2000. A retrospective design was used; all Canadian medical genetics centres and their affiliated laboratories offering genetic testing for HD were invited to participate. A total of 15 of 22 centres (68.2%), currently offering or ever having offered genetic testing for HD, responded, providing data on test results, demographics, and clinical history. A total of 1061 predictive tests, 15 pre-natal tests, and 626 diagnostic tests were performed. The uptake for predictive testing was approximately 18% of the estimated at-risk Canadian population, ranging from 12.5% in the Maritimes to 20.7% in British Columbia. There appears to have been a decline in the rate of testing in recent years. Of the predictive tests, 45.0% of individuals were found to have an increased risk, and a preponderance of females (60.2%) sought testing. A greater proportion of those at < or = 25% risk sought predictive testing once direct CAG mutation analysis had become available (10.9% after mutation analysis vs 4.7% before mutation analysis, p = 0.0077). Very few pre-natal tests were requested. Of the 15 pre-natal tests, 12 had an increased risk, resulting in termination of pregnancy in all but one. Diagnostic testing identified 68.5% of individuals to be positive by mutation analysis, while 31.5% of those with HD-like symptoms were not found to have the HD mutation. The positive diagnostic tests included 24.5% of individuals with no known prior family history of HD.     

The development and utility of a clinical algorithm to predict early HIV-1 infection

The association between self-reported clinical factors and recent HIV-1 seroconversion was evaluated in a prospective cohort of 4652 high-risk participants in the HIV Network for Prevention Trials (HIVNET) Vaccine Preparedness Study. Eighty-six individuals seroconverted, with an overall annual seroconversion rate of 1.3 per 100 person-years. Four self-reported clinical factors were significantly associated with HIV-1 seroconversion in multivariate analyses: recent history of chlamydia infection or gonorrhea, recent fever or night sweats, belief of recent HIV exposure, and recent illness lasting > or =3 days. Two scoring systems, based on the presence of either 4 or 11 clinical factors, were developed. Sensitivity ranged from 2.3% (with a positive predictive value of 12.5%) to 72.1% (with a positive predictive value of 1%). Seroconversion rates were directly associated with the number of these clinical factors. The use of scoring systems comprised of clinical factors may aid in detecting early and acute HIV-1 infection in vaccine and microbicide trials. Organizers can educate high-risk trial participants to return for testing during interim visits if they develop these clinical factors. Studying individuals during early and acute HIV-1 infection would allow scientists to investigate the impact of the intervention being studied on early transmission or pathogenesis of HIV-1 infection.