pp. 218-221 in Intractable Neurological Disorders, Human Genome Research and Society. Proceedings of the Third International Bioethics Seminar in Fukui, 19-21 November, 1993.

Editors: Norio Fujiki, M.D. & Darryl R.J. Macer, Ph.D.

Copyright 1994, Eubios Ethics Institute All commercial rights reserved by author. This publication may be reproduced for limited educational or academic use, however please enquire with Eubios Ethics Institute.

Genetic testing of children

Angus Clarke
Senior Lecturer, Dept. of Medical Genetics, University of Wales College of Medicine, Cardiff, U.K.

The question of whether testing children for "adult" or late-onset genetic disorders may be unethical has been raised for a number of conditions, particularly when there is no treatment available (1). Such testing removes the child's future right as an autonomous adult to decide whether or not to have the test performed, and also inevitably breaches the confidentiality to which an adult would be entitled. Furthermore, psychological damage may be inflicted upon the child despite the best intentions of family and professionals; parental expectations as to the child's future health, abilities, career, relationships and reproductive plans may all be altered by knowledge of the child's genetic status. Such altered expectations could influence the development of the child, and might become self-fulfilling prophecies. Where no medical harm would result, it might be better practice to defer such presymptomatic, predictive testing until the individual is adult.

Very similar issues are raised by childhood testing for carrier status for recessive disorders or for balanced chromosomal rearrangements; the results are of no immediate health benefit to the child, and only become relevant in the future when consideration is given to plans concerning relationships and reproduction. A summary of issues is given in Table 1.

Table 1: Predictive Testing in Childhood

Possible Advantages of Predictive Testing in Childhood
1 Relieves anxiety about possible early signs of the disorder.
2 Family uncertainty about the future is reduced.
3 More accurate genetic counseling becomes possible.
4 The child's attitude towards reproduction in adulthood will be more responsible.
5 Children who might benefit from genetic counseling in the future will be identified.
6 Practical planning for education, housing and family finances becomes possible.
7 Parental expectations of the child's behaviour become altered.

Possible Disadvantages of Predictive Testing in Childhood
1 Rarely leads to clarification of the genetic status of other family members.
2 Removes the child's right to decide whether or not to be tested in adulthood.
3 Leads to future difficulties in obtaining life insurance.
4 Parental expectations of the child's future reproductive behaviour become altered.
5 Damages the child's sense of self-esteem.
6 Generates unwarranted anxiety about possible early signs, before any genuine manifestation of the disorder.

The technical developments that permit such genetic tests to be performed at any stage of life from conception onwards are making these ethical questions ever more important. Unfortunately, there is very little evidence upon which to base rational policy decisions. For both potentially problematic situations, predictive testing for a late-onset disorder and carrier status testing, there are two core questions: is it good clinical practice to carry out such tests? and, who should be able to order such tests (parents, doctors, adoption agencies, insurance companies, schools or colleges, prospective employers?).

Concern about predictive genetic testing in childhood for Huntington's disease (HD) was first raised by Craufurd and Harris (2). Subsequently, a consensus was reached by the World Federation of Neurology that children should not be tested for it (3, 4). Now that predictive tests for HD have been available for some years, it is clear that the knowledge of HD gene status can be burdensome for an adult, even when the result is low risk (5), and only a minority of at-risk adults in fact choose to undergo such testing (about 10-15%) (6-8). The right of the child to decide in adult life whether or not to be tested would be removed if their genetic status was determined at the request of parents or others. Such requests have been made on many occasions (9, 10). At least in the case of HD, this knowledge could be harmful, because it might alter the behavioural and intellectual expectations of the child by the family in an unfavourable and self-fulfilling fashion (11). Particular harm could occur if a family have preselected the child, whether as affected or unaffected.

To what extent are these concerns unique to HD testing, and to what extent do these ethical considerations apply to other disorders too? Other neurodegenerative disorders, such as Alzheimer type or prion dementia (12), will clearly raise similar concerns. But the issues of principle - of autonomy and confidentiality - that are raised in this way by concerns over testing for HD could be said to apply across the board to predictive or carrier testing in childhood for any disorder.

Even when an at-risk child develops clinical features compatible with juvenile-onset HD, molecular genetic testing to determine whether or not the child has the HD gene may not necessarily be in the child's best interests (13, 11). Even if the child has the HD mutation, there may be another explanation for the child's neurological signs; the real explanation (perhaps treatable) may then be missed, and an inadvertent predictive test has been performed on a child.

The attitudes of health professionals in Britain to such testing has been investigated in a study carried out on behalf of a Working Party (chair AC) of the Clinical Genetics Society, and a wide range of attitudes and practices has been found. The diagnostic molecular genetic and cytogenetic laboratories in Britain were circulated with a questionnaire. Many of them carry out tests of carrier status on healthy children, although predictive tests are usually performed where some medical intervention may depend upon the result (e.g. screening for bowel tumours in familial polyposis coli).

More than 500 clinicians (predominantly paediatricians, haematologists, geneticists and genetic counsellors) responded to a separate questionnaire requesting information about their attitudes and practice in this area. It emerged that significant numbers of children do have their carrier status determined for a number of recessive disorders, but that practice varies widely and some clinicians regularly suggest that such tests be deferred until the child is older.

Table 2: Responses to Working Party Supplementary Questionnaire

Would you test a 5 year-old child whose parents wanted to know the genetic status for the following disorder(s) ?


Predictive Testing
Adult polycystic kidney disease 27 17 198 29
Charcot-Marie-Tooth 11 28 154 46
Huntington Disease 2 48 100 89
Hyperlipidaemias 40 7 223 16
Polyposis coli 28 16 214 14
Prion-protein dementia 0 42 66 48

Unaffected Carrier Status Testing
Cystic fibrosis 22 27 170 74
Haematological disease 22 28 155 74
Tay-Sachs 20 30 142 88
Adrenoleukodystrophy 12 32 132 74
Becker muscular dystrophy 11 33 136 82
Duchenne muscular dystrophy 14 32 163 75
(Balanced) chromosomal translocation 27 20 146 83

When asked about their attitudes to these issues, there were several areas where significant differences were found within and between groups. Only 20% of geneticists would give parents the right to have genetic tests (predictive or carrier status) performed on their children, while 75% of paediatricians and haematologists would do so. Less than 50% of geneticists and about 80% of paediatricians and haematologists agreed with the statement that it is up to the family to decide whether or not their child should be tested for genetic disorders.

A supplementary questionnaire was circulated to paediatricians and geneticists, asking whether or not the respondent would test an apparently healthy 5-year old child whose parents wanted to know the child's genetic status for a variety of variable dominant disorders (predictive testing) and for a variety of recessive disorders (for carrier status). Geneticists were generally less willing to carry out such tests, particularly for carrier status and for late-onset disorders, than were the paediatricians. The difference was particularly striking for HD and other late-onset dementias where very few geneticists would offer testing while a majority of the paediatricians who answered the question expressed a willingness to oblige the parents.

These differences of response are likely to reflect the different experiences of the professional groups. The caution of the geneticists might well arise from their experiences of the difficulties of dealing with such requests, while most paediatricians will never have been confronted with these issues (at least in the extreme case of testing for HD) in their clinical practice. The importance of the survey result is that the sudden availability of these tests through commercial laboratories might result in children being tested for these conditions because neither the families nor the clinicians involved have ever thought the issues through. It is therefore necessary to promote an awareness of these issues amongst the wider medical world outside clinical genetics.

For testing to identify carriers of recessive disorders in childhood the balance of the argument is less clear. While testing in childhood does ensure that the opportunity to perform the test is not lost, it does not ensure that the correct information will be given to the child in an appropriate fashion and at an appropriate age. Parents may have many different motives for requesting carrier status tests on their healthy children, and these may need to be explored before testing is performed. There are other, perhaps more satisfactory, ways in which carrier testing can be offered to children as they mature the maintenance of an active contact genetic register is one such way.

It can be argued that it is better for a child to know about their genetic status in childhood: this may then be accepted as a simple matter of fact, without the emotional problems that could arise from a later disclosure. An alternative view is that children should be encouraged to discuss the family's potential genetic problem at this early stage, but that the testing be deferred until the child is sufficiently mature to request the testing in their own right. This explicit granting of control to the child may actually be helpful in enhancing their self-esteem, and in allowing them to come to terms with possibly unfavourable results once they are adult.

We canvassed the views of genetic disease support groups - lay associations - and their members also expressed a great variety of different views ranging from the full "parental right to test" stance to the opinion that children should never be tested for such conditions. Several respondents voiced concerns about stigmatisation of the disabled and the poor social provision for them, and the harmful effects of genetic screening programmes aimed at "wiping out" (those with) genetic disorders.

There is little evidence available as to the practical effects of testing for genetic status, or refusing to test, in childhood; this is true for HD as well as for tests of carrier status. However, there is some evidence that knowledge of carrier status can have adverse effects in adults. Problems may arise with carrier testing because of stigmatisation or the fear of stigmatisation, even in an area where the carrier frequency is high (14). Adult carriers of Tay-Sachs have been shown to be less optimistic about their future health (15). An earlier study has shown that as many as 19% of Tay-Sachs carriers were worried about their carrier status (16), as were 10% of carriers of sickle cell and thalassaemia in Rochester, New York (17). The wider issues of social stigma have also caused concern even in the recent past, particularly in relation to population screening for sickle cell carrier status in the USA (18, 19). The limited experience with population screening for cystic fibrosis in Britain indicates that many adults, even those related to known carriers, decline the offer of screening tests (20).

In contrast to the situation in USA, where some authorities would grant parents the right to full genetic information on their offspring (21, 22), the law in Britain appears to be unlikely to impose childhood testing at parental request, so that rational policy development remains a possibility. Empirical studies are needed to assess the effects on families of disclosing predictive and carrier status genetic information about children to their parents. Accordingly, we (in Cardiff) are setting up studies to examine: 1) the effects of presymptomatic predictive testing for autosomal dominant polycystic kidney disease, where the medical benefits of testing are uncertain but potentially significant (a prospective study); 2) the long-term psychosocial effects of carrier status determination on children (in families with balanced chromosomal translocations and certain sex-linked disorders - a retrospective, qualitative study); 3) an in-depth examination of the conflicting attitudes towards childhood genetic testing discovered in the questionnaire study. It is hoped that this will help in the development of a professional consensus, which is needed to avoid arbitrary inconsistencies of practice between different clinicians, centres and disciplines.

Such empirical studies do not displace the consideration of the ethical issues, but they are certainly required if society is to arrive at a just consensus on these issues. One related area that will need to be monitored most carefully will be diagnostic screening of those with educational difficulties for fragile X or other causes of learning difficulties. The psychosocial and educational effects on children who are identified as carrying a fragile X; mutation will need to be studied carefully. For those who are already known to have moderate or severe learning difficulties, there may be little harm done; however, for those who are tested by screening because of minor learning problems or difficult classroom behaviour, there could be considerable damage from the stigmatising effects of this diagnostic label.

In concluding, I should add that I value the responses to this paper, particularly from my colleagues from Asia, Africa and South America. Perhaps the concerns felt in Britain about the possible harm done to children whose genetic status is determined in childhood appear bizarre to people from less individualistic, more family-focussed societies.


1. Harper PS, Clarke A (1990) Should we test children for "adult" genetic diseases ? Lancet 335: 1205-6.

2. Craufurd D, Harris R (1986) Ethics of predictive testing for Huntington's chorea: the need for more information. British Med. J 293: 249-251.

3. World Federation of Neurology: Research Committee Research Group (1989) Ethical issues policy statement on Huntington's disease molecular genetics predictive test. J Neurol Sci 94: 327-332.

4. World Federation of Neurology: Research Committee Group (1990) Ethical issues policy statement on Huntington's disease molecular genetics predictive test. J Med Genet 27: 34-38.

5. Huggins M, et al. (1992) Predictive testing for Huntington Disease in Canada: Adverse effects and unexpected results in those receiving a decreased risk. Am J Med Genet 42: 508-515.

6. Craufurd D, et al. (1989) Uptake of presymptomatic testing for Huntington's disease. Lancet ii: 603-5.

7. Tyler A, et al. (1993) Presymptomatic testing for Huntington's Disease in Wales 1987-1990. Brit J Psychiatry.

8. Bloch M, et al. (1992) Predictive testing for Huntington disease in Canada: The experience of those receiving an increased risk. Am J Med Genet 42: 499-507.

9. Morris M, et al. (1988) Adoption and genetic prediction for Huntington's disease. Lancet ii: 1069-70.

10. Morris, M. et al. (1989) Problems in genetic prediction for Huntington's disease. Lancet ii. 601-3.

11. Bloch M, Hayden MR (1990) Opinion: Predictive testing for Huntington disease in childhood: challenges and implications. Am J Hum Genet 46: 1-4.

12. Collinge J, et al. (1991) Presymptomatic detection or exclusion of prion protein gene defects in families with inherited prion diseases. Am J Hum Genet 49: 1351-1354.

13. Craufurd D, et al. (1990) Testing of children for "adult" genetic diseases. Lancet 335: 1406.

14. Stamatoyannopoulos G (1974) Problems of screening and counseling in the haemoglobinopathies, in (Motulsky AG & Ebling FJB, eds) Birth Defects: Proceedings of the Fourth International Conference. Amsterdam: Excerpta Medica.

15. Marteau TM, et al. (1992) Effects of genetic screening on perceptions of health: a pilot study. J Med Genet 29: 24-26.

16. Zeesman S, et al. (1984) A private view of heterozygosity: eight-year follow-up study on carriers of the Tay-Sachs gene detected by high school screening in Montreal. Am J Med Genet 18: 769-778.

17. Loader S, et al. (1991) Prenatal hemoglobinopathy screening IV Follow-up of women at risk for a child with a clinically significant hemoglobinopathy. Am J Hum Genet 49: 1292-1299.

11. Morris M, et al. (1989) Problems in genetic prediction for Huntington's disease. Lancet ii: 601-3.

18. Bowman JE (1991) Invited editorial: Prenatal screening for haemoglobinopathies. Am J Hum Genet 48: 433-438.

19. Kenen & Schmidt (1978) Stigmatisation of carrier status: social implications of heterozygote screening programmes. Am J Pub Health 68: 1116-1120.

20. Trembath RC, et al. (1991) Carrier testing for CFTR gene mutations in relatives identified through a cystic fibrosis prenatal testing service. Response rates and determinants of uptake. Clinical Genetics Society, Belfast.

21. Pelias MZ (1991) Duty to disclose in medical genetics: a legal perspective. Am J Med Genet 39: 347-354.

22. Sharpe NF (1993) Presymptomatic testing for Huntington disease: Is there a duty to test those under the age of eighteen years ? Am J Med Genet 46: 250-253.

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