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.     

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 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.     

Attitudes of neurologists, psychiatrists, and psychotherapists towards predictive testing for Huntington''s disease in Germany.

Predictive testing for Huntington's disease (HD) in Germany is performed by genetic counsellors, neurologists, psychiatrists, and psychotherapists. In order to evaluate the attitudes of neurologists, psychiatrists, and psychotherapists in Germany towards predictive testing for HD, a postal questionnaire was sent to this group. Two German Bundesländer were chosen, Baden Württemberg (BW) and Niedersachsen (NS). Of 469 persons interviewed the response rate was 32.6%. The questionnaire consisted of 17 items assessing sociodemographic data, acquaintance with HD patients, lay organisations, attitudes towards genetic counselling, presymptomatic and prenatal DNA testing, and reproduction of persons at risk for HD. More than 70% of the subjects were well informed about predictive DNA testing but knowledge about the details of the test procedure, especially the World Federation of Neurology (WFN) and International Huntington Association (IHA)1 recommendations, was quite low (11.8%). Nevertheless, the majority would recommend predictive testing for HD although they anticipated problems for the probands. The majority of our respondents favoured psychological test and post-test counselling for those tested. Concerning reproduction, most subjects favoured prenatal testing or that persons at risk should refrain from having children. We found that the opinions of practitioners and at risk persons differed with respect to the predictive DNA test and, particularly, to prenatal testing. Therefore the testing procedure could be improved if practitioners were better informed about the DNA test in general and about the attitudes and wishes of their patients.     

Attitudes toward presymptomatic testing and prenatal diagnosis for adrenoleukodystrophy among affected families.

One hundred and thirty-six individuals with a family history of X-linked adrenoleukodystrophy (ALD) or adrenomyeloneuropathy (AMN) were given a questionnaire surveying their sociodemographic characteristics, knowledge of X-linked inheritance, and attitudes toward prenatal, presymptomatic, and carrier testing. Of the respondents, 68% indicated that they would use prenatal testing. Of these, 57.1% would terminate a pregnancy of a male fetus hemizygous for the ALD gene and 13.5% would reportedly choose to terminate a heterozygote female fetus. Presymptomatic testing would be used by 88.7% of respondents to test at-risk sons and carrier testing would reportedly be used by 95.4% of respondents to test their at-risk daughters. Respondents correctly answered an average of 61% of the questions testing understanding of X-linked inheritance. This indicates a strong interest in prenatal, presymptomatic, and carrier testing and a need for genetic counselors to provide information about these available tests and X-linked inheritance.     

Attitudes toward presymptomatic testing and prenatal diagnosis for adrenoleukodystrophy among affected families

One hundred and thirty-six individuals with a family history of X-linked adrenoleukodystrophy (ALD) or adrenomyeloneuropathy (AMN) were given a questionnaire surveying their sociodemographic characteristics, knowledge of X-linked inheritance, and attitudes toward prenatal, presymptomatic, and carrier testing. Of the respondents, 68% indicated that they would use prenatal testing. Of these, 57.1% would terminate a pregnancy of a male fetus hemizygous for the ALD gene and 13.5% would reportedly choose to terminate a heterozygote female fetus. Presymptomatic testing would be used by 88.7% of respondents to test at-risk sons and carrier testing would reportedly be used by 95.4% of respondents to test their at-risk daughters. Respondents correctly answered an average of 61% of the questions testing understanding of X-linked inheritance. This indicates a strong interest in prenatal, presymptomatic, and carrier testing and a need for genetic counselors to provide information about these available tests and X-linked inheritance.     

Knowledge, attitude, and the decision to be tested for Huntington's disease

In September 1986, the Baltimore Huntington's Disease Project initiated a voluntary program of presymptomatic genetic testing for Huntington's Disease (HD). Forty-seven persons at 50% risk for HD attended one of two educational sessions designed to educate them about the test. At the beginning and end of each session, subjects completed the Affect Adjective Checklist and a set of questions assessing knowledge about and attitude toward presymptomatic testing. As a result of attending an educational session, subjects learned more about presymptomatic testing, and their attitude towards finding out whether they had the marker for the HD gene became more favorable. Fewer people requested genetic testing than expected. Those who later chose to undergo genetic testing had a more favorable attitude at both the beginning and at the end of the educational session. The significance of these data for genetic counselors is discussed.     

Attitudes of at-risk and affected individuals regarding presymptomatic testing for autosomal dominant polycystic kidney disease

One hundred forty-one individuals with autosomal dominant polycystic kidney disease (ADPKD) and 137 at-risk individuals from 107 kindreds answered a questionnaire to determine knowledge and attitudes about ADPKD and the use of gene linkage analysis for prenatal and postnatal presymptomatic diagnosis. Both groups of individuals displayed a high level of knowledge about the disease. Although 87% of affected individuals considered the recurrence risk of ADPKD high, only 11% of ADPKD did not have children for this reason after diagnosis. Ninety-seven percent of at-risk individuals would utilize gene testing for themselves. Eight-eight percent of ADPKD and 89% of at-risk individuals would test offspring (not significant, NS) and 65% of ADPKD and 50% of at-risk individuals between the ages of 18 and 40 would use prenatal testing (NS). Only 4% of ADPKD and 8% of at-risk individuals between the ages of 18 and 40 would terminate a pregnancy for ADPKD. A greater percentage would terminate a pregnancy for a serious medical problem. The factors influencing presymptomatic testing were analyzed. The data suggest that presymptomatic testing will not substantially modify incidence of ADPKD since it may only occasionally alter reproductive plans.     

Huntington's disease: do future physicians and lawyers think eugenically?

The availability of presymptomatic and prenatal genetic tests could give rise to societal pressures on persons at risk for Huntington's disease (HD). The objective of this study was to identify future lawyers' and physicians' views on eugenics and genetic testing for HD. Five-hundred and ninety-nine Swiss law students and advanced medical students from 11 courses received teaching about HD and patient autonomy. They filled out questionnaires after having seen an audio/video recording of an interview with an HD mutation carrier. Participation rates were 68-97%. Attitudes of future lawyers and physicians were significantly different for most questions: 73.2% of law students vs 39.4% of medical students agreed that society should do everything possible to diminish the frequency of HD, including non-governmental pressure on carriers to undergo systematic genetic testing and recommendation of sterilization; 94% of all students agreed to the systematic proposal of prenatal testing to all women at risk; and 83.4% of medical students, but only 40.3% of law students, agreed that the wishes of a person at risk not to have her/himself and future children tested must be entirely respected. More education is needed to discourage eugenic pressures and discrimination of persons at risk of HD and other genetic diseases.     

Huntington's disease in Greece: the experience of 14 years

A large scale genetic and epidemiological study of Huntington's disease (HD) was carried out in Greece from January 1995 to December 2008. Diagnostic testing was carried out in 461 symptomatic individuals, while 256 were tested for presymptomatic purposes. The diagnosis of HD with a CAG expansion ≥ 36 was confirmed in 278 symptomatic individuals. The prevalence of HD in Greece was estimated at approximately 2.5 to 5.4:100,000, while the mean minimum incidence was estimated at 2.2 to 4.4 per million per year. The molecular diagnosis of HD was confirmed in the majority of patients (84.4%) sent for confirmation. The false-positive cases 15.6% were characterized by the absence of a family history of HD and the presence of an atypical clinical picture. The uptake of predictive testing for HD was 8.6%. A prenatal test was requested in six pregnancies. The findings of our study do not differ significantly from those of similar studies from other European countries despite the relative genetic isolation of Greece. Of interest is the identification of clusters of HD in Greece. The presence or absence of a family history of HD should be interpreted cautiously, during the diagnostic process.     

Attitudes of Dutch general practitioners towards presymptomatic DNA-testing for Huntington disease

The attitudes of 1020 Dutch GP's towards presymptomatic and prenatal testing for Huntington disease (HD) were studied by means of a postal questionnaire. The questionnaire contained questions about: approval of presymptomatic DNA-testing, informing individuals at-risk who do not request predictive testing, referral to a clinical genetics center, and opinions about different strategies of informing and supporting individuals at-risk. The response rate was 62%. More than two-thirds of the GP's considered post-test counselling and support as their responsibility. Twenty-six per cent were of the opinion that the test results should be disclosed by the GP. Fifty-nine per cent of GP's who had an individual at-risk in their practice were familiar with the test. The attitudes of GP's towards giving support and giving test results were independent of familiarity with the test and the incidence of HD-patients or at-risk individuals in the practice. Although GP's were willing to play an important role in presymptomatic DNA-testing procedures, there is a risk that they might underestimate the difficulties in communicating genetic information and the psychosocial effects of DNA-testing. Hence, we favor the premise that extensive pretest counselling and test disclosure should remain the prime responsibility of the clinical geneticist. Increasing involvement of GP's should, however, be encouraged and combined with appropriate postgraduate education about predictive DNA-testing in general.     

Molecular diagnosis of Huntington disease in Portugal: implications for genetic counselling and clinical practice

Huntington disease (HD) is a neurodegenerative, autosomal dominant disorder of late-onset, caused by the expansion of a CAG repeat in the coding region of the gene. Ours is the reference laboratory for genetic testing in HD, in Portugal, since 1998; 90.1% of all 158 families known were identified for the first time, including patients with unusual presentation or without family history. A total of 338 genetic tests were performed: 234 for diagnosis, 96 for presymptomatic and four for prenatal testing (four were done for family studies). Most referring physicians were neurologists (90.6%); 82.8% of all clinical diagnosis were confirmed, while 83.1% of those sent for exclusion were in fact excluded. In presymptomatic testing, an excess of female subjects (59.4%) was again verified; 37.5% of the consultands were found to be carriers. None of the foetuses, in four prenatal tests, were mutation carriers. One juvenile case was inherited from her mother. Our patient population is very similar to others described so far, namely in terms of mean age at onset and (CAG)(n) distribution, except perhaps for a higher frequency of large normal (class 2) alleles (3.7%). We also identify cases posing particular problems for genetic counselling, such as, 'homozygosity' that can pose a serious ethical dilemma, carriers of large normal alleles, and 'homoallelism' for a normal gene, which will demand further procedures and may delay results in presymptomatic and prenatal testing.     

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.     

Potential impact of a predictive test on the gene frequency of Huntington disease

Fifty-five individuals at 50% risk of inheriting Huntington disease (HD) were given in-depth structured interviews to survey attitudes toward use of a predictive test and to assess the possible impact of such a test on the number of gene carriers born. Three-quarters of the sample said they would take predictive test. Given a positive predictive or prenatal test, the number of individuals choosing to have children is reduced from 80% of the total sample to 42%, or by almost one-half. The large proportion of at risk individuals who say they would use a predictive test underscores the importance of developing guidelines for its administration prior to implementation.     

To know or not to know: a review of behaviour and suicidal ideation in preclinical Huntington's disease

OBJECTIVE: At present, the problems associated with suicidal ideation and suicide in Huntington's disease (HD), worldwide, are much the same as 2 decades ago. This study seeks to investigate the psychological complications of predictive testing in HD at risk populations. METHODS: The key problems of predictive testing, fear of acquiring carrier status, psychological consequences, autonomy, and rights to know are discussed. RESULTS: This review (1) describes psychological affect and problems of persons facing the decision to test for HD, (2) discusses suicidal ideation, behaviour, and catastrophic events associated with predictive testing, (3) assesses ethical questions raised in the genetic counselling, (4) questions whether counsellors should promote or advocate predictive testing, and finally (5) discusses what professionalism actually is in genetic counselling. CONCLUSION: The need for professional counselling, using a well designed protocol, and the importance of focusing on the suicide risk of participants in predictive testing programs are emphasized. PRACTICE IMPLICATIONS: The counsellor has an obligation to provide adequate information. The professionals should not promote nor advocate presymptomatic DNA-testing. Depression, hopelessness, anxiety, emotional distress, suicidal tendencies, and social dysfunction grading should be considered in predictive testing of HD.     

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.     

New tools for preimplantation genetic diagnosis of Huntington's disease and their clinical applications

Huntington's disease (HD) is a late-onset neurodegenerative disorder transmitted as an autosomal dominant trait. The causative mutation was characterised in 1993. For HD carriers willing to create a family, prenatal diagnosis (PND) or preimplantation genetic diagnosis (PGD) based on the mutation identification can be offered. For at-risk persons who do not want to undergo presymptomatic testing (PT), an exclusion test can be proposed. With such a test, only foetuses or embryos that inherit an allele from the unaffected grandparent are considered as unaffected. In cases of PND, if the foetus has one allele of the affected grandparent, termination of pregnancy is proposed. In cases of PGD, only not at-risk embryos are transferred. Since the beginning of our PGD activity, we have had 43 PGD referrals for HD, of which 24 were from patients who know their genetic status and 19 from patients who do not wish to perform PT. We have developed 12 multiplex fluorescent PCR protocols applied at the single-cell level for PGD, some of which target the CAG repeat while others use two different polymorphic microsatellites. We present here these different protocols and their clinical applications, as well as the characterisation and use of a new highly polymorphic intragenic marker. Between May 2001 and December 2003, 39 PGD cycles have been performed for 17 couples, 11 of whom had a known genetic status and six who did not wish to perform PT, resulting in four pregnancies.     

Predictive testing for Huntington disease: social characteristics and knowledge of applicants, attitudes to the test procedure and decisions made after testing

An investigation has been made of the social characteristics and knowledge and experience of Huntington disease (HD) for the first 80 individuals considering presymptomatic testing (applicants) at the medical genetics centres in Edinburgh and Glasgow and of attitudes to the test procedure and decisions made after testing for those who received a result. Sixty-one percent of applicants were female and 31% were over 40 years old. Almost all had a symptomatic parent but 38% did not know HD was in their family until they were over 25 years old and 48% had never received genetic counselling. Thirty-eight percent of applicants first heard of the test at the genetic clinic, 20% from a relative and 20% from the media, but none had received information from their GP. Thirty-one applicants did not have the test because they voluntarily withdrew (17 individuals), their family structure was unsuitable or no informative result was possible (11 individuals), or they were diagnosed clinically as being affected (3 individuals). Those who voluntarily withdrew did not differ significantly from the 49 who received a result in social characteristics or knowledge and experience of HD. Twenty-two individuals were found to be at increased risk (IR) (>50% of becoming affected) and 27 to be at decreased risk (DR) (< 50% of becoming affected). There was a median period of 9 months between entering the test procedure and receiving a result and the main criticism of the procedure was that it took too long to complete and several individuals experienced considerable anxiety while awaiting their result. One year after receiving their result, almost 40% of individuals had made major life decisions, mainly in the areas of personal relationships, career and financial matters and over a third of fecund individuals in both IR and DR groups had changed their decision about future childbearing. Eighty-five percent of the IR group and 53% of the DR group requested continued follow up after the 1-year follow-up visit. The majority wanted follow up by the genetic clinician, but we have found that in practice many individuals do not attend when offered clinic appointments after this time.     

Protocol for genetic testing in Huntington disease: three years of experience in Minnesota.

Molecular genetic testing for Huntington disease (HD) by linkage analysis of DNA markers close to the HD gene has been possible since the mid-1980s. Because of ethical and practical concerns about this kind of testing, most groups performing the test in the past have operated under lengthy research protocols designed to assess the psychological morbidity of the presymptomatic diagnosis of a fatal disease. Our approach to HD testing is service-oriented, and our testing process has been designed to be flexible, to meet the varying needs of our patients. Between 1988 and 1990, 87 inquiries about the test have been received; 22 inquiries had family structures which were unsuitable for linkage analysis. Eleven of the 37 individuals who entered the testing program have not completed it. Of 19 patients who have received DNA results, seven received an increased risk of carrying the HD gene, and ten, a decreased risk. For two additional individuals, nonpaternity resulted in a negligible risk for HD. Several of those consulted, or their spouses, have had continuing outpatient counseling since completing the test; none have required hospitalization. Our short-term results indicate that molecular genetic testing for HD can be performed safely in a clinical setting using our protocol. As molecular genetic testing for HD and other diseases moves out of research centers and into clinics, clinicians must devise practical strategies for providing the medical, genetic, and psychological services needed for the growing number of individuals who will seek such testing.     

Attitudes toward prenatal genetic testing for Treacher Collins syndrome among affected individuals and families

Treacher Collins syndrome (TCS) is a craniofacial syndrome that is both phenotypically variable and heterogeneous, caused by mutations in the TCOF1, POLR1C, and POLR1D genes. We examined attitudes towards TCS prenatal genetic testing among affected families using a telephone questionnaire. Participants were 31 affected adults and relatives recruited primarily through families cared for in the mid-Atlantic region. Nineteen participants (65%) reported that they would take a TCS prenatal genetic test which could not predict degree of disease severity. Interest in TCS genetic testing was associated with higher income, higher concern about having a child with TCS, lower religiosity, lower concern about genetic testing procedures, and having a sporadic rather than familial mutation. Over half reported that their decision to have TCS genetic testing would be influenced a great deal by their desire to relieve anxiety and attitudes toward abortion. Ten participants (32%) reported that they would be likely to end the pregnancy upon receiving a positive test result; this was lower amongst TCS affected individuals and higher amongst participants with children with TCS. Genetics healthcare providers need to be aware of affected individuals' and families' attitudes and interest in prenatal genetic testing for TCS, and the possible implications for other craniofacial disorders, so that patients' information needs can be met.