SHOULD CHILDREN AND ADOLESCENTS BE TESTED FOR HUNTINGTON’S DISEASE? ATTITUDES OF FUTURE LAWYERS AND PHYSICIANS IN SWITZERLAND

The objective of the study was to identify future lawyers' and physicians' views on testing children for Huntington's disease (HD) against parents' wishes. After receiving general information about HD, patient autonomy and confidentiality, law students and advanced medical students were shown an interview with a mother suffering from HD who is opposed to informing and testing her two children (aged 10 and 16) for HD. Students then filled out questionnaires concerning their agreement with testing. No significant differences were found between medical and law students or between students from different courses concerning the adolescent son. Three quarters of students thought that he should be told about his mother's disease, and 91% thought the adolescent son should have the opportunity of genetic testing for HD himself. However, significant differences were found concerning the 10-year old son, with 44% of law students and 30% of medical students in favour of testing the child for HD. Students raised some important ethical issues in their elective comments. In conclusion, we found highly positive attitudes towards informing a 16-year old of his mother's HD and offering to test him. These attitudes were not in tune with guidelines. Students did not consider several practical and ethical issues of genetic testing of children and adolescents. Specific education should ensure that attitudes are based on sufficiently detailed knowledge about all aspects of genetic testing of children to discourage pressures on persons at risk of HD.     

Proceed with Care: Direct Predictive Testing for Huntington Disease

The cloning of the Huntington disease (HD) gene allows highly accurate predictive testing using direct analysis of the CAG repeat. This new test provides results with almost complete certainty but poses unique counseling issues related to direct testing for an adult-onset disease. These include testing individuals who are at 25% risk, without the need for blood from a 50% at risk relative; the assessment of symptomatic individuals; the need for ongoing counseling despite simplification of laboratory procedures; and counseling of persons from families who represent a new mutation for HD. This paper describes protocols for direct predictive testing for adult and prenatal assessment, on the basis of the experience of the Canadian Collaborative Study on Predictive Testing (CCSPT). Over the past 8 years, we have provided >400 results by using linked markers and, more recently, 416 results by using direct assessment of CAG expansion in the HD gene. The vast majority (86%) of requests for direct predictive testing have been from persons who have not previously received results by using linked markers. Despite the ability to now directly assess for the mutation associated with HD, we still recommend assessment of DNA from an affected relative, as this may significantly enhance the accuracy of information to be provided to the at-risk individual. Distance from a genetics center has previously limited the availability of testing, and therefore we have developed approaches to providing predictive testing in the patient's own community.     

Predictive testing for Huntington disease: nonparticipants compared with participants in the Dutch program.

Attitudes toward predictive testing programs, in individuals who choose not to undertake the test (i.e., nonparticipants), may be influenced by fears of an unfavorable result. The reasons not to participate in predictive testing programs for Huntington disease (HD) were studied in members of the Dutch Huntington Association who were at 50% risk. They had completed the same baseline psychological questionnaires as had the participants in the Dutch DNA-testing program. The group of 34 nonparticipants was similar to the tested participants in the Dutch predictive testing program, with respect to average age (31.1 years), male:female ratio (1:2), the frequency of a stable relationship (70%), and level of education (67% had high school education or higher). Testing did not seem to be a realistic option for nonparticipants for improving their quality of life. In comparison with participants, nonparticipants had a significantly more pessimistic outlook on themselves and their futures. When asked to consider the possibility of an unfavorable result, nonparticipants expected more difficulties in their families; more problems for their children, their partners, and themselves; a lowered quality of life; and, more often, a depressive reaction. In their opinion, a favorable result would reduce the problems for their children but not for themselves, a result that was found more often in the nonparticipant than in the participant group. Nonparticipants learned about their being at risk for HD during adolescence (mean age 15.6 years), whereas participants did so in adulthood (mean age 22.7 years). The nonparticipants' attitude toward the test might be explained by the influence of HD in the adolescent's separation-individuation process and personality development. This finding could be relevant for future research and for the discussion about testing minors for delayed-onset disorders.     

Research samples from families with genetic diseases: a proposed code of conduct.

Research on samples from families with genetic disease underlies many of the major advances that are occurring in medical genetics. But ethical and practical problems may arise when samples from relatives who are healthy but at risk are included in such studies. In particular, new molecular tests for specific gene mutations may result in the detection of a genetic defect in relatives who had neither expected this possibility nor given specific consent to such testing. Family members at risk should not be included in such studies unless strictly necessary, and in such cases specific consent should be obtained and information should be given about the implications of an abnormal result of a test. This is particularly important when stored samples from previous studies without such implications are being reused and is also relevant to the genetic testing of samples taken primarily for epidemiological studies of disorders when only a small proportion of cases is thought to be genetic in origin. There is a need for guidelines to protect both subjects and investigators in a field which is spreading rapidly and involving many clinical and laboratory research workers previously unfamiliar with genetic testing.     

Gender differences in attitudes among those at risk for Huntington's disease

This report presents and discusses selected findings regarding gender differences from an Australian-based study that investigated attitudes of individuals at risk for Huntington's disease (HD) towards genetic risk and predictive testing. Clear gender differences emerged regarding perceived coping capacity with regard to predictive testing, as well as disclosure of the genetic risk for HD to others. Female participants were more likely to disclose their genetic risk to others, including their medical practitioners, while male participants were three times more fearful of disclosing their genetic risk to others. These findings are of interest in light of gender differences that have consistently been reported regarding the uptake of predictive testing for HD, other genetic conditions, and health services more generally. While gender differences cannot provide a fully explanatory framework for differential uptake of predictive genetic testing, men and women may experience and respond differently to the genetic risk for HD and possibly other inherited disorders. The meanings of genetic risk to men and women warrants further exploration, given anticipated increases in genetic testing for more common conditions, especially if post-test interventions are possible. These issues are also relevant within the context of individuals' concerns about the potential for discrimination on the basis of genetic risk or genetic test information.     

Isolation and characterization of new highly polymorphic DNA markers from the Huntington disease region.

The defect causing Huntington disease (HD) has been mapped to 4p16.3, distal to the DNA marker D4S10. Subsequently, additional polymorphic markers closer to the HD gene have been isolated, which has led to the establishment of predictive testing programs for individuals at risk for HD. Approximately 17% of persons presenting to the Canadian collaborative study for predictive testing for HD have not received any modification of risk, in part because of limited informativeness of currently available DNA markers. Therefore, more highly polymorphic DNA markers are needed, which will further increase the accuracy and availability of predictive testing, specifically for families with complex or incomplete pedigree structures. In addition, new markers are urgently needed in order to refine the breakpoints in the few known recombinant HD chromosomes, which could allow a more accurate localization of the HD gene within 4p16.3 and, therefore, accelerate the cloning of the disease gene. In this study we present the identification and characterization of nine new polymorphic DNA markers, including three markers which detect highly informative multiallelic VNTR-like polymorphisms with PIC values of up to .84. These markers have been isolated from a cloned region of DNA which has been previously mapped approximately 1,000 kb from the 4p telomere.     

Genetic tests obtainable through pharmacies: the good,the bad,and the ugly

Genomic medicine seeks to exploit an individual’s genomic information in the context of guiding the clinical decision-making process. In the post-genomic era, a range of novel molecular genetic testing methodologies have emerged, allowing the genetic testing industry to grow at a very rapid pace. As a consequence, a considerable number of different private diagnostic testing laboratories now provide a wide variety of genetic testing services, often employing a direct-to-consumer (DTC) business model to identify mutations underlying (or associated with) common Mendelian disorders, to individualize drug response, to attempt to determine an individual’s risk of a multitude of complex (multifactorial) diseases, or even to determine a person’s identity. Recently, we have noted a novel trend in the provision of private molecular genetic testing services, namely saliva and buccal swab collection kits (for deoxyribonucleic acid (DNA) isolation) being offered for sale over the counter by pharmacies. This situation is somewhat different from the standard DTC genetic testing model, since pharmacists are healthcare professionals who are supposedly qualified to give appropriate advice to their clients. There are, however, a number of issues to be addressed in relation to the marketing of DNA collection kits for genetic testing through pharmacies, namely a requirement for regulatory clearance, the comparative lack of appropriate genetics education of the healthcare professionals involved, and most importantly, the lack of awareness on the part of both the patients and the general public with respect to the potential benefits or otherwise of the various types of genetic test offered, which may result in confusion as to which test could be beneficial in their own particular case. We believe that some form of genetic counseling should ideally be integrated into, and made inseparable from, the genetic testing process, while pharmacists should be obliged to receive some basic training about the genetic tests that they offer for sale.     

Is There a Case in Favour of Predictive Genetic Testing in Young Children?

Genetic testing technology has brought the ability to predict the onset of diseases many years before symptoms appear and the use of such predictive testing is now widespread. The medical fraternity has met the application of this practice to children with caution. The justification for their predominantly prohibitive stance has revolved around the lack of a readily identifiable medical benefit in the face of potential psychological harms to the child. We argue that predictive testing can have important psychosocial benefits and that the interests of the child have been construed too narrowly. Proponents of a prohibitive stance also argue that testing in childhood breaches the child's future right to make the same decision as an autonomous adult and to maintain this information as confidential. We argue that predictive genetic testing of children is not necessarily a violation of the child's future autonomy. Indeed, in some cases, such testing may facilitate the development of autonomy in the maturing child. We argue that parents are generally best placed to judge what is in their own child's overall interests, and that a parental request for testing after appropriate genetic counselling should be respected unless there is clear evidence that the child will be harmed in an overall sense as a result of testing.     

Presymptomatic testing for Huntington's disease

Summary Presymptomatic testing for Huntington's disease (HD) is possible through the use of restriction fragment length polymorphisms (RFLPs) at the closely linked D4S10 locus. Recombination between the HD and D4S10 loci will occur in 4%–5% of meioses, and is a well-recognised complication of predictive testing. Recombination between RFLPs within the D4S10 locus is a rare event and can usually be ignored. We report a case where such an intra-locus recombination frustrated attempts to predict the chance of a high-risk individual inheriting the HD gene.     

Non-uptake of predictive genetic testing for BRCA1/2 among relatives of known carriers: attributes, cancer worry, and barriers to testing in a multicenter clinical cohort

BRCA1/2 test decliners/deferrers have received almost no attention in the literature and this is the first study of this population in the United Kingdom. The aim of this multicenter study is to examine the attributes of a group of individuals offered predictive genetic testing for breast/ovarian cancer predisposition who did not wish to proceed with testing at the time of entry into this study. This forms part of a larger study involving 9 U.K. centers investigating the psychosocial impact of predictive genetic testing for BRCA1/2. Cancer worry and reasons for declining or deferring BRCA1/2 predictive genetic testing were evaluated by questionnaire following genetic counseling. A total of 34 individuals declined the offer of predictive genetic testing. Compared to the national cohort of test acceptors, test decliners are significantly younger. Female test decliners have lower levels of cancer worry than female test acceptors. Barriers to testing include apprehension about the result, traveling to the genetics clinic, and taking time away from work/family. Women are more likely than men to worry about receiving less screening if found not to be a carrier. The findings do not indicate that healthy BRCA1/2 test decliners are a more vulnerable group in terms of cancer worry. However, barriers to testing need to be discussed in genetic counseling.     

Risk reduction and health promotion behaviors following genetic testing for adult-onset disorders

Although clinical genetic testing is available for over 1,000 inherited disorders, consequences of predictive genetic testing have been most extensively examined for hereditary breast and ovarian cancer (HBOC), hereditary colon cancer, and Huntington disease (HD). These focus primarily on psychological, ethical, legal, and social aspects of genetic testing. Genetic testing may also provide information that can lead to behaviors that promote health and reduce risk for disease, reflecting options available for the disorder for which the person is at risk. However, regardless of condition, people completing a genetic test may inform relatives about the results of the test and implications for their risk to develop the condition. Literature on risk reduction behaviors and communication focuses on families with HBOC or colorectal cancer. Few reports document behaviors for other conditions. This paper presents a systematic review of the research literature on risk reduction and health promotion behaviors following clinical genetic testing for adult onset conditions, primarily HBOC, familial colon cancers, and HD. Insights gleaned from this review are discussed as a basis for planning monitoring of health promotion and risk-reduction behaviors for genetic testing for present and future use.     

Predictive Psychiatric Genetic Testing in Minors: An Exploration of the Non-Medical Benefits

Predictive genetic testing for susceptibility to psychiatric conditions is likely to become part of standard practice. Because the onset of most psychiatric diseases is in late adolescence or early adulthood, testing minors could lead to early identification that may prevent or delay the development of these disorders. However, due to their complex aetiology, psychiatric genetic testing does not provide the immediate medical benefits that current guidelines require for testing minors. While several authors have argued non-medical benefits may play a crucial role in favour of predictive testing for other conditions, little research has explored such a role in psychiatric disorders. This paper outlines the potential non-medical benefits and harms of psychiatric genetic testing in minors in order to consider whether the non-medical benefits could ever make such testing appropriate. Five non-medical themes arise in the literature: psychological impacts, autonomy/self-determination, implications of the biomedical approach, use of financial and intellectual resources, and discrimination. Non-medical benefits were prominent in all of them, suggesting that psychiatric genetic testing in minors may be appropriate in some circumstances. Further research needs to empirically assess these potential non-medical benefits, incorporate minors in the debate, and include normative reflection to evaluate the very purposes and motivations of psychiatric genetic testing in minors.     

Genetics providers and the family covenant: connecting individuals with their families

As genetic testing becomes more commonplace, medicine will likely face both family and individual demands for access to, and control of, test result information. Past research has emphasized confidentiality concerns of the individual and contrasted these claims with the "need to know" by others to avoid harm. These confidentiality concerns, based on individual self-interest, are challenged by a singularly important aspect of genetic testing-familial responsibility. As patients are often motivated to obtain genetic testing by an array of "other-directed" considerations toward their own family (such as love, fiduciary responsibility, gratitude, etc.), an accounting of these concerns is warranted. Understanding the relevance of family relationships and obligations facilitates a fuller informed consent for genetic testing. Genetic counselors and geneticists engaging in genetic counseling can account for the concerns of both individuals and their families using the family covenant-a helpful, innovative model to address proactively boundaries of privacy and information sharing within the family. This model focuses on two areas of discussion: (1) the demarcation of the boundaries of confidentiality; and (2) the definition of "family." The family covenant helps genetics providers consider what information "should" be confidential, and with respect to whom.     

Professional and personal attitudes about access and confidentiality in the genetic testing of children: a pilot study

The ability to perform predictive genetic testing of children raises ethical concerns regarding whether and when to test and the disclosure of results. Semi-structured interviews with a convenience sample of pediatricians (12) and geneticists (13) were conducted to see how they would react to parental requests for predictive genetic testing of their children, and their attitudes about testing their own children. We also asked about disclosure attitudes and practices for their patients' relatives and within their own families. Respondents would provide predictive genetic testing for most conditions, yet were less likely to seek this information about their own children. Respondents believed it was very important for patients to share some types of genetic information with relatives, and were directive in their counseling about intrafamilial disclosure, especially within their own families. Although respondents would almost never breach patient confidentiality, many would breach confidentiality within their own families. Health care professionals distinguish between their professional and personal roles with regard to issues of access and confidentiality in predictive testing of children. They are willing to provide greater access and more confidentiality for their patients than within their own families.     

Common SNP-based haplotype analysis of the 4p16.3 Huntington disease gene region

Age at the onset of motor symptoms in Huntington disease (HD) is determined largely by the length of a CAG repeat expansion in HTT but is also influenced by other genetic factors. We tested whether common genetic variation near the mutation site is associated with differences in the distribution of expanded CAG alleles or age at the onset of motor symptoms. To define disease-associated single-nucleotide polymorphisms (SNPs), we compared 4p16.3 SNPs in HD subjects with population controls in a case:control strategy, which revealed that the strongest signals occurred at a great distance from the HD mutation as a result of "synthetic association" with SNP alleles that are of low frequency in population controls. Detailed analysis delineated a prominent ancestral haplotype that accounted for ～50% of HD chromosomes and extended to at least 938 kb on about half of these. Together, the seven most abundant haplotypes accounted for ～83% of HD chromosomes. Neither the extended shared haplotype nor the individual local HTT haplotypes were associated with altered CAG-repeat length distribution or residual age at the onset of motor symptoms, arguing against modification of these disease features by common cis-regulatory elements. Similarly, the 11 most frequent control haplotypes showed no trans-modifier effect on age at the onset of motor symptoms. Our results argue against common local regulatory variation as a factor influencing HD pathogenesis, suggesting that genetic modifiers be sought elsewhere in the genome. They also indicate that genome-wide association analysis with a small number of cases can be effective for regional localization of genetic defects, even when a founder effect accounts for only a fraction of the disorder.     

Linkage disequilibrium and modification of risk for Huntington disease.

The major limitation in performing predictive testing for Huntington disease (HD) is the unavailability of DNA from crucial family members. In our program approximately 20% (36/183) of persons have been excluded from predictive testing because of this reason. The major aim of this study was to examine whether data derived from linkage disequilibrium could modify risk analysis for persons at risk for HD. As a first step, we assessed whether the previously reported linkage disequilibrium between alleles recognized by probe pBS674E-D at locus D4S95 remained significant in a much larger data set. A total of 1,150 chromosomes from 622 individuals--200 affected and 422 unaffected--from 118 families were assessed. Significant haplotype association was detected with AccI and MboI RFLPs at the locus D4S95, with all the families (P = .00003), as well as for a subset from the United Kingdom (P = .0037). Data derived from linkage disequilibrium studies using D4S95 modifies the risk for HD, especially in persons of U.K. descent. Utilization of this approach for risk modification of HD awaits both validation of these data and additional information concerning ethnic-specific alleles at the D4S95 locus.     

The V471A Polymorphism in Autophagy-Related Gene ATG7 Modifies Age at Onset Specifically in Italian Huntington Disease Patients

The cause of Huntington disease (HD) is a polyglutamine repeat expansion of more than 36 units in the huntingtin protein, which is inversely correlated with the age at onset of the disease. However, additional genetic factors are believed to modify the course and the age at onset of HD. Recently, we identified the V471A polymorphism in the autophagy-related gene ATG7, a key component of the autophagy pathway that plays an important role in HD pathogenesis, to be associated with the age at onset in a large group of European Huntington disease patients. To confirm this association in a second independent patient cohort, we analysed the ATG7 V471A polymorphism in additional 1,464 European HD patients of the “REGISTRY” cohort from the European Huntington Disease Network (EHDN). In the entire REGISTRY cohort we could not confirm a modifying effect of the ATG7 V471A polymorphism. However, analysing a modifying effect of ATG7 in these REGISTRY patients and in patients of our previous HD cohort according to their ethnic origin, we identified a significant effect of the ATG7 V471A polymorphism on the HD age at onset only in the Italian population (327 patients). In these Italian patients, the polymorphism is associated with a 6-years earlier disease onset and thus seems to have an aggravating effect. We could specify the role of ATG7 as a genetic modifier for HD particularly in the Italian population. This result affirms the modifying influence of the autophagic pathway on the course of HD, but also suggests population-specific modifying mechanisms in HD pathogenesis.     

A worldwide assessment of the frequency of suicide, suicide attempts, or psychiatric hospitalization after predictive testing for Huntington disease

Prior to the implementation of predictive-testing programs for Huntington disease (HD), significant concern was raised concerning the likelihood of catastrophic events (CEs), particularly in those persons receiving an increased-risk result. We have investigated the frequency of CEs-that is, suicide, suicide attempt, and psychiatric hospitalization-after an HD predictive-testing result, through questionnaires sent to predictive-testing centers worldwide. A total of 44 persons (0.97%) in a cohort of 4,527 test participants had a CE: 5 successful suicides, 21 suicide attempts, and 18 hospitalizations for psychiatric reasons. All persons committing suicide had signs of HD, whereas 11 (52.4%) of 21 persons attempting suicide and 8 (44.4%) of 18 who had a psychiatric hospitalization were symptomatic. A total of 11 (84.6%) of 13 asymptomatic persons who experienced a CE during the first year after HD predictive testing received an increased-risk result. Factors associated with an increased risk of a CE included (a) a psychiatric history 相似文献   

Genetic testing and genetic counseling among medicaid-enrolled children with autism spectrum disorder in 2001 and 2007

The rise in the prevalence of autism spectrum disorder (ASD) has resulted in increased efforts to understand the causes of this complex set of disorders that emerge early in childhood. Although research in this area is underway and yielding useful, but complex information about ASD, guidelines for the use of genetic testing and counseling among children with ASD conflict. The purpose of this study was to determine the frequency of use of genetic testing and counseling before the widespread implementation of clinical chromosomal microarray (CMA) to establish a baseline for the use of both services and to investigate potential disparities in the use of both services among children with ASD. We found that about two-thirds of children with ASD received genetic testing or counseling and the use of both services is increasing with time, even in the pre-CMA era. Being female and having a comorbid intellectual disability diagnosis both increased the likelihood of receiving genetic testing and genetic counseling. Initial discrepancies in the use of both services based on race/ethnicity suggest that troubling disparities observed in other services delivered to children with ASD and other mental health disorders persist in genetic testing and counseling as well. These results should incentivize further investigation of the impact of genetic testing and counseling on children with ASD and their families, and should drive efforts to explore and confront disparities in the delivery of these services, particularly with the advancing scientific research on this topic.     

Genetic predictive testing for bowel cancer predisposition: the impact on the individual.

When considering the impact of a genetic diagnosis of hereditary predisposition to colon cancer, there are many similarities to other predictive genetic tests, but also many differences. The development and availability of such genetic diagnoses, and the concept of testing being linked to effective prevention, have advanced rapidly, opening up not only unique opportunities but also unique psychosocial situations for the affected families-and unusual ethical issues for the professional. Compared to a diagnosis of sporadic colorectal cancer for a patient, hereditary colorectal cancer requires an understanding of genetics, heredity, and the attendant mathematics of risk calculation, but, most importantly, there must be a belief that it is possible to remain healthy whilst having an increased risk. This paper outlines the possible impact of a genetic diagnosis of hereditary non-polyposis colorectal cancer (HNPCC) or familial adenomatous polyposis (FAP) on both the individual and the family and concludes that genetic testing should be accompanied by genetic counseling. Relevant ethical issues are also introduced, with the opinion presented suggesting that if primary considerations are always for the individual rather than the family or society, then unethical or eugenic decisions are likely to be avoided.