Journal ofMedical Ethics, 1996; 22: 105-110

Genetic testing and early diagnosis andintervention: boon or burden?Elizabeth R Hepburn IBVM Queensland Bioethics Centre, Brisbane, Australia

AbstractThe possibility of early diagnosis and intervention isradically changed by the advent ofgenetic testing. Therecent report of the Nuffield Council on Bioethics istimely and helpful. I have suggested, that not only theseverity of the disability indicated by geneticinformation, and the accuracy of the data, ought togovern the approach to the implementation of screeningfor genetic disorders. In addition, assessment of the valueof the information to those involved should beconsidered. The efficacy of the available therapeuticmeasures, combined with the prognostic data areimportant indices of the value of the information. Thesemeasures fall into three categories and thus indicate thatthree different courses of intervention may beappropriate. Three approaches to diagnosis andintervention are then outlined, drawing on theexperience of various clinical initiatives.

IntroductionThe notion that early diagnosis and intervention isimportant therapeutically is almost an article of faithin medicine. The advent of genetic testing raises thepossibility of a re-definition of "early". The prospectof disease and disability can be detected reliably andearly in the case of phenylketonuria (PKU) andtesting in the first week of life has become routine.The Human Genome Project promises the identifi-cation of all inherited genetic abnormalities prior tobirth. Whilst growing use of prenatal testing mightwork against the interests of the child, as the practiceacquires the characteristics of quality control and wedemand "perfect" offspring; the potential for fetaltherapy may also work against the interests of themother, who may be required to submit to invasiveprocedures in the service of the baby. However,genetic mapping will permit diagnosis and interven-tion earlier than during fetal development.' It ispossible to identify the carriers of genetic defects andwarn them of the risk of abnormalities, such as Tay-Sachs disease. In this case "early" is not merely

Key wordsPrenatal diagnosis; genetic screening; ethics.

prenatal, but preconception. Moreover, the beststrategy will often be behavioural rather than strictlymedical.

Diagnostic investigation raises questions aboutthe status of the fetus, the rights of parents withrespect to children, our understanding of normality/abnormality and whose interests are really served byour increasing application of diagnostic testing.2 Itputs into question the claim that early intervention isalways for the best. It may be that genetic finger-printing will be both boon and burden. We need toask ourselves for whom, and when, and under whatcircumstances, genetic screening will provide morebenefit than harm. Our answers to such questionsare ultimately answers to the question of what itmeans to be human.

Proposals to institute massive screening pro-grammes for genetic defects ought to be viewed withcaution. The recent Nuffield Council on Bioethicsrecommendations on genetic screening (1993),whilst timely and cautious, are like earlier authorita-tive statements,3 rather too broad to guide policyand practice. It seems to me that there are criticaldifferences between the tests for disease, both interms of their timing and specificity, and in terms ofthe nature of the disease itself, which influence theway in which we ought to deal with issues of policy.However, the Nuffield report suggests principleswhich ought to govern policy and practice, namely:that screening be voluntary and the results treated asconfidential; that counselling and education be avail-able to potential participants, and that the use ofgenetic test results by employers and health insurersbe restricted and conditioned by the interests of theemployee or client. I will show that three scenarios,differentiated by the nature of the interventionpossible following diagnosis, require three differentapproaches, which are consistent with the Nuffieldprinciples.

Illness and abnormalityThe prospect of reducing the frequency of congenitalabnormalities seems to be a logical extension ofprenatal care and in keeping with the promotion ofhealth and wellbeing. The advent of these techniques

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106 Genetic testing and early diagnosis and intervention: boon or burden?

raises questions too. The very definition of "normal"comes into sharp relief and the decision as to what todo when an abnormality is detected becomes a more

frequent occurrence. As Hannah Arendt asked so

pointedly: "Who has the right to determine who shallinhabit the world?"4 And how will those appointed tothis task make their decisions?

Rothman5 has pointed out that disability is a socialconstruct. In countries where sex selection is permit-ted the rate of male births far exceeds female birthsand it is probably true that in many societies girls andwomen are so socially disadvantaged that femalegender may be construed as a disability. Indeed,Fletcher6 sees the prospect of widespread sex

selection serving to relegate female sex to thecategory of a genetic disorder. Rothman is concernedthat the availability of genetic testing will diminishour tolerance of difference and that ever-increasingquality control will be demanded. The emergence ofa new form of tort - litigation in which either childrenhold their parents responsible for their "wrongful"life,7 or in which parents sue doctors for wrongfulbirth,8 supports Rothman's claim.A side-effect of a growing intolerance of con-

genital variation construed as abnormality may beto exacerbate the disadvantage already suffered bythose members of our society who are seen as

disabled. The extension of testing carries a very clearmessage of rejection to such people. The availabilityof a diagnostic test creates a sense of protection fromabnormality and parental disappointment and rejec-tion may be heightened as a result. Before we

embark on further development or institute screen-

ing procedures, we need to explore, as a society,what we understand by notions of normality andhow far we are prepared to tolerate deviation fromsuch a socially determined norm.

Those who have experienced prenatal testing,especially in the form of ultrasound, testify to theheightened awareness of the developing entity as a

child. The tests themselves can strengthen the bondbetween parents and child at an early stage in thepregnancy. Indeed, Fletcher8 thinks that progress infetal therapy will tend to elevate the status of thefetus. Yet the purpose of the diagnostic test is topermit a decision to intervene either therapeutically,or in some cases, to end the life of a fetus for whomtherapy is not possible, or to prepare for the birth ofa disabled child. The decision to abort requires dis-tancing, especially for the mother, precisely at a timewhen relatedness has just been emphasised.9Parents, and mothers in particular, are faced with a

conflict exacerbated by the technology itself. Just atthe moment of recognition of the embryo as a livingentity, it may be suggested that this life be ended.

Whose rights?The prospect of two physicians attending pregnantwomen, but with differing expertise and concerns,

raises the possibility of mutually exclusive courses oftherapeutic action being proposed. The argumentwhich might then arise would be like an extension ofthe current pro-choice/pro-life argument. Very oftenthe debate is couched in terms of rights and this beingso, it is important, as many have pointed out, to estab-lish the moral status of the fetus. Is the fetus an entitywhich can properly be said to have rights or interests?

Progress in both neonatology and fetal therapywill orient us to viewing the fetus as a patient. Thisnew category of patient may be seen as having a rightto health care, apparently conferring the status ofperson on the fetus. Certainly in some jurisdictionsin the United States the fetus is seen as having rightsto protection from harm. There have been cases inwhich action has been brought against pregnantwomen who were exposing their offspring to terato-genic agents by taking various drugs. There is alsolegislation permitting discrimination against womenin the workplace, in order to avoid possible fetalinjury through exposure to teratogenic hazards.'0Yet if the fetus carries an abnormality not amenableto treatment, although not lethal, will the fetus bedisenfranchised as a patient? If so, it seems theassumed personal status of the fetus is contingent onnormality and we would face again the dilemmaswhich anti-discriminatory legislation, such as the USPeople with Disabilities Act, seeks to eliminate. Onthe other hand, some might claim that euthanasia inthe form of abortion, is the right of the disabledfetus, indeed, is in that patient's interests.

Duty of careThe crux of the argument is whether it is actually thefetus on whom rights are conferred or to whominterests are ascribed, or if such attribution is contin-gent on the decision to protect the life of the child.Traditionally the life of the fetus was defended invirtue of its potential to become a full member of thehuman community." Now it seems that for somethe decision as to whether the pregnancy will besupported to term determines whether the develop-ing child will be protected from harm. Thus manyargue that although abortion is justifiable, thedecision to bring a child to birth implies a duty ofcare, even prenatally. The same people campaignboth for the right to abortion and for the right of theunborn child to protection from prenatal assault orinjury. In a sense, rights are not conferred on thefetus but are claimed on behalf of the future child,the born person the fetus has the potential tobecome. My own view is that these claims should behonoured from conception, that we ought notchoose to end the life of even a potential person.Exploration of these issues, along with those onwhich I have chosen to focus, must be part of thepublic debate about early diagnosis and genetictesting, since abortion will be an option when a gravecondition is detected. Greater accuracy in diagnosis

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Elizabeth R Hepburn 107

may result in a higher incidence of medicallyindicated abortion and polarisation of the abortionissue will not serve us well in the long term.

Testing and investingIn modem Western societies it is often relativelysimple to encourage people to seek diagnostictesting. Culturally, the ascendancy of science hasengendered a growing desire to exert control overevents and to reduce uncertainty. In some situationsdiagnostic testing can provide a means to both ends.Yet the value of the knowledge gleaned from diag-nostic tests is questionable. In a highly entertainingessay Clifton Meador,'2 recently made the observa-tion that the last well person in the world is going tobe enmeshed in so many defensive practices s/he willscarcely have time to enjoy being well. There is aserious point to this, namely the evaluation ofwhether particular items of information are desir-able. It reflects our deepest convictions and commit-ments. It is not true that information is neutral, thatour response to it is what determines its value andmeaning. There is such a thing as "bad news"; earlydiagnosis of an invariably fatal condition beforethe onset of a disease such as amyotrophic lateralsclerosis (ALS or Lou Gehrig's Disease), is just oneexample. Where ignorance is bliss, it may indeed, befolly to be wise.

All of this takes on another dimension when theinformation is not about oneself but a dependentother with no capacity for autonomous action ordecision. In such circumstances, it is normal to makea decision which minimises risk to that individual. Arisk we assess as worthwhile on our own account,may often seem too great to undertake on behalf ofanother. Expectant parents are in a very vulnerableposition. Society encourages risk minimisation andcontrol. Not to protect one's offspring by everymeans available amounts to dereliction of duty andadded to that is the natural alternation of hope andapprehension about the birth of a new child. In mostcases, parents are dependent on expert advice andmay feel quite incompetent to make choices betweentreatments. Many will seek maximal protection andrisk reduction, any test available will be seen asnot only a boon, but a necessity. In such a setting,the likely market for prenatal diagnostic tests isenormous.

Diagnosis is the first step in establishing treatmentoptions, and identification of genetic abnormalitiesmay occur soon after birth, during pregnancy, atconception or prior to conception. Howeverpowerful and accurate genetic screening testsbecome, there will always be a margin of error andsome genetic abnormalities will not be detected untilafter birth. Identification of a genetic abnormalityduring pregnancy permits immediate therapeuticintervention; a decision can be taken to support orterminate the pregnancy. Should all means to

promote life be pursued or does serious disabilityinfluence the way in which we evaluate therapeuticintervention? Prospective parents who carryabnormal genes could select healthy early embryosusing in vitro fertilisation (IVF) procedures whichwould permit inspection of the early embryo beforetransfer. A problem which then arises, is what is tobe done with the genetically abnormal embryo.Nevertheless, intervention at the time of conceptionobviates decisions about whether to maintain andcomplete a pregnancy and how to treat the disabledchild after birth.The diagnostic information itself indicates three

different sorts of intervention. First, there may bethe identification of an inherited or congenitalabnormality which is easily detected after birth, andsimple and cheap to treat, an example would bephenylketonuria (PKU). Second, there may be theidentification of a gene which always causes a diseasefor which there is no treatment and which is alwaysfatal, for instance, Tay-Sachs disease. Third, it maybe possible to identify a gene which predisposes thecarrier to a life-threatening disease, for which there istreatment but no cure, such as, for example, a breastcancer gene (BRCA 1). 3 In each case, the responseto the information is modified by the likely outcomeand the efficacy of available treatment. It is, there-fore, reasonable to assume that the approach toscreening for each category of disease should be dif-ferent. Of the three, the third is presumably going tobe the most common once the human genome ismapped. In these circumstances knowledge of one'sgenetic complement may be boon or burden.

Cost-effectiveThe detection of phenylketonuria (PKU)'4 15through routine screening of urine of newborns is agood example of the way in which early diagnosismay be critical. The genetic disorder is easily andcheaply detected and it is a relatively simple matterto protect the newbom from exposure to the poten-tially damaging phenylalanine. The diet prescribed isfree of this amino acid. For PKU both detection andtreatment are relatively straightforward. Further, thespecial diet provides protection against the expres-sion of the disease. That is, in the case of PKU bothhereditary and modifiable environmental factorsinfluence outcome. In fact, routine screening forPKU occurs in most Western health care settings.The test is clearly in the best interests not only of theinfant, but also of the parents and society, sincethere is a cost-effective way of treating the disease.The possibility of detecting the breast cancer gene

(BRCA1) has given rise to suggestions that womenin families known to be susceptible to early onsetbreast cancer be screened for the gene."6 Of thosecarrying the gene some 80 per cent are expected todevelop disease.'7 So 20 per cent, for some reason,carry the gene but do not ever show signs of disease.

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108 Genetic testing and early diagnosis and intervention: boon or burden?

Just as with PKU, the expression of disease is notdependent on the presence of the gene alone. UnlikePKU though, treatment for breast cancer is difficult,costly, risky and often unsuccessful. Treatmentoptions range from radical, bilateral mastectomy as ateenager or participation in a Tamoxifen trial, tocareful monitoring and conventional treatment ifand when disease appears. Even if the first option istaken, there is no guarantee of freedom from cancer.In either case, knowledge of the presence of the geneis likely to heighten not only awareness, but appre-hension. In such families awareness is alreadypresent. The genetic test merely confirms the suspi-cion. Possession of the gene does not sentence one todisease, nor does its absence guarantee freedomfrom disease. Yet the way in which we speak ofgenetic testing implies that the test is definitive:accurate and absolute. Until a means of replacing orblocking the action of the BRCA1 gene is available,the value of having the information is equivocal.The capacity to detect the BRCA1 gene raises

further questions. Who should have access to theinformation? At what age should girls be informed ofthe test, be tested and be informed of their geneticstatus? Should those men and women carrying thegene commit themselves to childlessness in order tostem the passage of the gene to future generations?Should these people be advised to enter in vitrofertilisation (IVF) programmes, so that disease-freeembryos could be selected prior to implantation?These questions attend tests for every identifiableinherited disease. It is probably true that each of uscarries genetic portenders of our ultimate cause ofdeath. When the human genome is mapped how willwe determine the limits of normality and who shouldbe tested? The dream of a population free of geneticdefect will not be achieved simply by knowledge ofthe genome, it will require the implementation of asocial policy which can justify the elimination ofunwanted genes.

At present, the elimination of unwanted genes willdepend on restriction of reproduction. Death of theactual weakest would be supplanted by exclusion ofthe potential weakest. The human population couldbe managed in the same way as animal herds. In fact,a group of Hassidic Jews in New York has adoptedjust such a strategy in dealing with Tay-Sachsdisease. Marriages are arranged so that the disease isnot passed on. In a relatively small, closed com-munity such a scheme is possible, but for the widercommunity it seems more problematic. However, inMontreal there has been some success in screeningyoung people for particular diseases. The pro-gramme has operated through schools, and has beensupported by a sound and effective educational pro-gramme. Groups known to be at risk for Tay-Sachsdisease, 3-thalassaemia and cystic fibrosis have beenoffered genetic testing during their late adolescentyears. A follow-up study showed that eight yearsafter testing, participants were glad to have the infor-

mation and were in favour of making genetic testingavailable.'8 Informing likely carriers of abnormalgenes permits them to make informed and respon-sible choices about their future reproductivebehaviour.The vision of a world free of inherited disease is

presented by commercial interests, as not only desir-able, but possible. Medical expenditure would bechannelled from care facilities to drug companiesand laboratories. In prospect we will be beguiled bythe thought that prevention is better than cure. Inreality, we will have lost sight of the fact that life is aterminal condition and that health care, whateverthe cause of disease, is an on-going expense. Itwould be premature, if not foolish, to consider thatthe removal of all inherited diseases would reduceoverall health care expenditure. I am not suggestingthat we do not proceed with genetic and fetalresearch, or that such knowledge is not helpful, Iam simply warning that it may not bring all theadvantages it promises. Further, it is clear that weneed to find ways of using diagnostic procedures andinformation well, so that the dignity of the individualis honoured, and the value of the interventionprocess is tangible to the person concerned.

Using diagnostic information wellI have suggested that the realisation of the dream ofa population free of inherited defects would dependas much on public policy as on biomedical know-ledge. Clearly, the strength of the Hassidic com-munity policy is that it is democratically determinedby a majority, and there is consent to the practice byall involved. The individuals are treated within suchan arrangement as ends in themselves, they are self-determining in the matter. In this situation familiar-ity with the disease, access to accurate informationand the apparent consent of all involved removessome of the concerns associated with notions ofselective breeding in human populations. Thosemaking the policy of restriction are themselves thesubjects of the constraints, constraints which areviewed collectively as essential to the health, andeven survival, of the community. The group wantedto remain both homogeneous and healthy. Therewere two distinct and strong incentives to implementsuch a policy.

Secondly, the disease itself is not only fatal buthorribly debilitating through its progress. There isno treatment for the disease. No one could viewTay-Sachs disease as manageable or tolerable. Itspatterns of passage from one generation to anotherare well understood. There is no way of dealing withthe disease other than to eradicate it. The alter-natives to arranged marriages, barring the use of newreproductive technologies, would be to accept thestatus quo or to enforce childlessness for many, ifnot most, thus ensuring the decline of the com-munity as an entity.

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Elizabeth R Hepburn 109

Thirdly, it is possible to see this strategy as short-term: within a few generations the disease could beeradicated from the community. The social changeis instituted in the interests of the life of the com-munity as an on-going entity. It is not envisaged thatthe social change will be permanent. In the case ofPKU, identification, treatment and control were allsimply and cheaply achieved. There was no stigmaattached to having the disease and it was in thepatient's best interests to establish PKU status andinitiate treatment as soon as possible. Further, as evi-denced in Montreal too, when the screening pro-gramme is accompanied by sound and effectivepublic health education, those tested regard the infor-mation as beneficial and access to tests as a service.

It seems to me that there are a number of lessonswe can draw from the Hassidic experience andsuccessful screening programmes for congenitaldiseases such as PKU, to employ within the widercommunity.

* First, genetic tests should only be usedroutinely to prevent the occurrence of diseases whichare universally regarded as causing intolerable suf-fering or to detect those for which there is a simpleand cheap cure or preventative measure.

* Second, genetic screening should be restrictedto those diseases which are well understood, that is,the certainty of the information should provide asufficient basis from which an individual can act, andfor which adequate genetic counselling is available.

* Third, as a public health measure, educationalprogrammes should focus on those inheriteddiseases for which there is reasonable hope of pre-vention, and eventually of eradication, by voluntaryagreement of those who would undergo screening, tohalt the passage of the genes involved.

* Finally, it is critical that all such programmesare backed by sound public health education, andthat there is not only broad public approval of thepolicy, but also the opportunity for individuals not tobe disadvantaged if they elect not to participate inscreening programmes.

All of these considerations are further modified bythe accuracy of the genetic test. Not all tests are con-clusive. Issues of probability in relation to diagnosisshould be a prominent aspect of both educationalprogrammes and the advice given in counselling.Often press releases from research laboratories givethe impression that the results of testing areunequivocal and absolutely accurate. In view of thetendency of those engaged in this work to be notonly enthusiastic but perhaps too optimistic aboutthe outcome of testing it would seem wise toseparate the educational and counselling servicesfrom the clinical setting. A precaution observed bymany in vitro fertilisation (IVF) clinics is the separa-tion of the functions of organ procurement andreplacement in organ transplant procedures. It is

hoped that such an arrangement will minimisepossible conflicts of interest and protect bothprospective parents and children from exploitation.

I have concerned myself here only with prenataltesting for disability and disease and primarily withthose diseases known to have a genetic basis. Thequestion of enhancing the genotype of offspring'9 isimportant and raises another set of issues. Thequestion is likely to attract attention in places witheither private or mixed funding for health care. Incountries in which health care is largely publiclyfunded it is likely that taxpayers would baulk atfooting the bill to indulge the desires of parents forsay, blonde, athletic offspring. The view that healthcare is a human right and its provision a communityresponsibility, will put limits on what is seen aslegitimate health care.20

In contrast, it would seem that in the UnitedStates the "free-market" ethos, which sees medicineas a commodity, will spawn practitioners keen tocorner a new market niche: the "designer child" willbe available. Arguments relating to this issue mustbe cast in as wide a context as possible, examiningsome of the issues already mentioned, such as rejec-tion when expectations of a perfect child are unmet;lost opportunities of resources allocated to seeking a"perfect" baby rather than, perhaps, health care ofthe parents and the less "perfect" siblings of such achild, and the societal implications of rejecting thehybrid, happy children many of us have been,despite our imperfections. For this reason, the rec-ommendation of the Nuffield Council on Bioethicsfor further work by the Department of Health (UK)in establishing criteria and review processes for thepractice of genetic screening, is to be welcomed.

ConclusionI have suggested that since the results of genetictesting differ greatly in terms of therapeutic value,screening policies should reflect these differences. Insituations in which the tests are known to beaccurate and the appropriate treatment is simple andcheap, screening programmes accompanied bysound and effective educational programmes seemto be appropriate public health measures. In caseswhere the transmission of the defective gene willresult in the birth of offspring with serious anduntreatable disabilities, it is suggested that compre-hensive educational programmes targeted at specificgroups be conducted in late adolescence (prior tochildbearing), and genetic testing and counselling bemade available. This puts those affected in posses-sion of the information they require in order to makeinformed reproductive choices. The last and mostproblematic group is that for which genetic factorsindicate a predisposition to a specific disease forwhich there is no adequate treatment. It is inappro-priate to embark on wholesale screening in such cir-cumstances and it is even questionable whether such

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110 Genetic testing and early diagnosis and intervention: boon or burden?

information will be construed as boon or burden bythose affected. The experience of people living withAIDS2' and those who have had breast cancer,18suggests that the most helpful thing which medicinehas to offer is honest information, and sensitive andrespectful assistance with decision-making. Not totell patients the "bad news" ultimately works againstthe interests of all concemed.

AcknowledgementsThis paper was prepared during my time as aVisiting Scholar at the McGill Centre for Medicine,Ethics and Law. I am grateful to all who made mewelcome there and to the Loreto sisters for theirgenerous support of this time of study. TheQueensland Bioethics Centre is at 18 ClarenceStreet, South Brisbane, Australia, 4101 and servesthe five Catholic dioceses of Queensland. Sr RegisMary Dunne RSM, the founding Director, helped toclarify several technical points.

Elizabeth R Hepburn, IBVM, BSc(Hons), MA, PhD,is Director of the Queensland Bioethics Centre, Brisbane,Australia.

References and notes1 The terms "baby", "child", and "fetus" may all be used

of the one entity. The function of technical language isto create distance. I think it is helpful to retain the rela-tional language, of "child" and "baby", in determininghow best we can deal with conflicts of interest whenthey arise. It also underscores my own view that thefetus is due the protection owed to a person and thatthe fetus is best regarded as a person and a patient.

2 It also raises questions about the rights of parents toseek modification of the genotype to enhance capaci-ties. Here, I deal only with issues associated with theuse of prenatal testing for disabilities.

3 Wilson J, Junger G. Principles and practice ofscreeningfordisease. Geneva: World Health Organisation, publichealth papers No 34, 1968.

4 Arendt H cited by Hubbard R. Eugenics: new tools,old ideas. In: Baruch EH, D'Adamo AF, Seager J, eds.Embryos, ethics and women's rights. New York:Harrington Press, 1988: 225-36.

5 Rothman B. Reproductive technology and the com-modification of life. In: Baruch EH, D'Adamo AF,Seager J, eds. Embryos, ethics and women's rights. NewYork: Harrington Press, 1988: 95-100.

6 Fletcher JC. Ethical issues in genetic screening andantenatal diagnosis. Clinical Obstetrics and Gynecology1981;24: 1151-68.

7 It should be noted that the majority of jurisdictions donot at present recognise the right of a child to complainabout having been born. Shaw M. The potential plain-tiff: preconception and prenatal torts. In: Milunsky A,Annas GJ, eds. Genetics and the law II. New York:Plenum, 1980: 225-32.

8 Dickens B. Wrongful birth and life, wrongful deathbefore birth and wrongful law. In: McLean SAM, ed.Legal issues in human reproduction. Aldershot: Gower,1989: 80-112.

9 Hubbard R. Eugenics: new tools, old ideas. See reference6: 225-36.

10 Daniels CR. At women's expense. Cambridge, MA:Harvard University Press, 1993.

11 Noonan JT. An almost absolute value in history. In:Noonan JT, ed. The morality of abortion. Cambridge,MA: Harvard University Press, 1970.

12 Meador CK. The last well person. New EnglandJournalofMedicine 1994; 330: 440-1.

13 This gene had not been identified when the report wasprepared so these possibilities were not considered.

14 PKU is inherited through two recessive genes, one fromeach parent.

15 Similar points could be made with respect to a screen-ing programme for Rh-negative factor in maternalblood. Testing is routine. Treatment is straightforward(either, immunisation of Rh-negative mothers orexchange transfusion of blood for the baby) and effec-tive, if undertaken in utero or in the first few hours oflife.

16 Batt S. Patient no more. Charlottetown, Prince EdwardIsland: Gynergy, 1994.

17 Figures vary, 80 per cent is an estimate only. Ford D,Easton DF, Bishop DT, Narod SA, Goldgar DE. Risksof cancer in BRCAI-mutation carriers. Lancet 1994;343: 692-6, indicates 87 per cent penetrance of thebreast cancer gene by age 70. Easton D. Breast-ovariancancer families and the BRCA1 gene. Lancet 1994;343: 711, indicates carriers have a 50 per cent risk ofbreast cancer by age 50, 70 per cent by age 70. EastonDF, Bishop DT, Ford D, Crockford GP. Geneticlinkage analysis in familial breast and ovarian cancer:results from 214 families. American J7ournal of HumanGenetics 1993; 52: 678-701 indicates carriers have acumulative risk of 59 per cent by age 50, 82 per cent by70.

18 Zeesman S, Clow C, Cartier L, Scriber C. A privateview of heterozygosity: eight year follow-up study oncarriers of the Tay-Sachs gene detected by high schoolscreening in Montreal. American Jrournal of HumanGenetics 1984; 18: 769-78.

19 The technical capacity to enhance human genotypes isnot currently available.

20 See Leary V. The right to health in international humanrights law. Health and Human Rights 1994; 1: 24-57.

21 Shilts R. And the band played on. New York: Bantam,1988.

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