| 3.
Ethics in genetic research and practice |
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3.3
Genetic screening and testing
Essentially,
the screening process may be divided into three phases - the
preparation of the participant or patient; the analysis of the
genetic material; the interpretation of the analysis coupled
with ensuing support programmes.25 It is useful to
distinguish between these three phases in a discussion of the
ethics of genetic screening and testing. During the preparatory
phase, ethical considerations revolving around informed consent
must be addressed. The analysis phase raises familiar issues
such as adequacy of procedure and confidentiality with respect
to the participant or patient. The final phase raises ethical
concerns relating to the management of genetic disorders and
the subsequent impact of the screening process on the individual
and his or her family.25
Genetic
screening should be distinguished from genetic testing at the
outset. The terms are often used interchangeably, although they
represent two different forms of genetic practice. Genetic screening
is carried out on groups of people, which could consist of a
section of the population defined by age, sex, or other risk
factor, or a subgroup within the population, or within broad
groups in which genetic factors may be responsible for certain
disabilities.26 Genetic screening may be defined
as:
"...
a search in a population to identify individuals who may have,
or be susceptible to, a serious genetic disease, or who, though
not at risk themselves, as gene carriers may be at risk of having
children with that genetic disease."26
Genetic
testing, on the other hand, leads to a definitive diagnosis
in individuals, and is defined to be:
"...
the analysis of a specific gene, its product or function, or
other DNA and chromosome analysis, to detect or exclude an alteration
likely to be associated with a genetic disorder."25
Individuals
may desire testing where there is a family history of a specific
disease, if they exhibit symptoms of a genetic disorder; or
if they are concerned about passing on genetic disorders to
their children.27 In addition, genetic testing in
individuals is used as a 'fingerprint' in forensics. The areas
of focus for genetic testing at present are thus carrier and
susceptibility testing, prenatal diagnosis, newborn testing,
and forensic testing.28
Screening
programmes play a useful part in public health care systems
in identifying potentially serious risks that can be prevented
by timely treatment.i Testing allows couples the possibility
of making informed choices about parenthood and, possibly, in
identifying genetic susceptibility to common serious diseases.26
Three goals have been identified for genetic screening:26
- to contribute
to improving the health of persons who suffer from genetic
disorders;
- to allow
carriers for a given abnormal gene to make informed choices
regarding reproduction; and
- to move
towards alleviating the anxieties of families and communities
faced with the prospect of serious genetic disease.
A fourth
goal could be added to this list - the reduction of public health
costs. Genetic screening is an attractive option for those institutions
seeking to manage their public health exposure. It is feared
that the greater our ability to predict the costs of heritable
diseases, the greater the public pressures on adults not to
pass on genes that are associated with particularly bad outcomes.29
Pressure may also be brought to bear on individuals to be tested
for genetic predispositions and to act "to save society
long- term costs resulting in a new eugenics based, not on undesirable
characteristics, but rather on cost-saving."28
However,
some consider any aspirations to a 'healthy public' to be misguided
because genetic control of the human population, or any form
of 'genome cleansing' could easily slide into eugenics.30 Others
hold the view that genetic screening at embryo level will take
place in developed countries, and if this is not done in developing
countries the discrepancy between the two will widen even further.
3.3.1
Scientific basis
Inheritance
is determined by the genes, of which there are an estimated
32 000 in the human genome. Genes are large molecules made up
of a substance, DNA, whose double helical structure allows both
copying and division. The particular sequence of individual
chemical sub-units in a gene serves as a molecular code to specify
the manufacture of a particular protein. An alteration (mutation)
at even a single position of the DNA sequence may cause serious
malfunction of the resulting protein. Modern advances in genetics
are due to the ability to study DNA directly. At present we
have, at best, information on only one-third of the genes.
The genes
are arranged in a fixed order on the chromosomes. Chromosomes
are elongated strings of DNA and protein that occur in the nucleus
of every cell in the body. Unlike genes, chromosomes can be
seen through a light microscope, especially when they become
compacted during cell division. In the normal human there are
two sets of 23 chromosomes, 46 in all, one set having been inherited
from the father, the other from the mother. The members of 22
of the 23 pairs appear identical: these are the autosomes. The
remaining pair, the sex chromosomes, differ between males and
females; females have a pair of X chromosomes whereas a male
has one X chromosome (inherited from his mother) and one Y chromosome
(inherited from his father).
Medical
genetics is part of the human genetics concerned with the role
of genes in illness. Traditionally, the analysis of the genetic
contribution to illness and human characteristics has been divided
into:
- disorders
due to changes in single genes;
- disorders
influenced by more than one gene (polygenic); and
- chromosomal
disorders.
In addition
to the genetic contribution, the environment often plays an
important part in influencing both the onset and severity of
disease, particularly in the polygenic disorders.
3.3.1.1
Single gene diseases
Inherited
single gene diseases may show three common types of inheritance
pattern.
- Autosomal
dominant: such diseases (Huntington's disease, for instance)
result from one of a pair of matched autosomal genes having
a disease-associated alteration, the other being normal. The
chance of inheriting the altered gene from an affected parent
is 1 in 2 in each pregnancy. Autosomal dominant diseases commonly
affect several individuals in successive generations.
- Autosomal
recessive: these diseases (such as cystic fibrosis) require
the inheritance from both parents of the same disease-associated
abnormal autosomal gene. The parents are usually themselves
unaffected, but are gene carriers. When both parents carry
the same altered gene, the chance of inheriting two altered
genes and thereby of having the disease is 1 in 4 in each
pregnancy. Autosomal-recessive diseases usually only affect
the brothers and sisters within a single generation; the incidence
of the disease in individuals in previous or subsequent generations
is usually very small. Hence diseases with this form of inheritance
tend to occur 'out of the blue'.
- X-linked:
diseases due to genes on the X chromosome (such as haemophilia)
show a special inheritance pattern: they are also known as
sex-linked disorders. Most X-linked conditions occur only
in males who inherit the abnormal gene from their mothers.
These mothers are carriers of the altered gene but are usually
unaffected themselves, because their other X chromosome has
the normal gene (as in auto-somal-recessive disease). Females
may occasionally show some features of the disease, depending
on the condition. An affected male never transmits the disease
to his sons. When the mother carries a gene for an X- linked
disease, the chance of inheriting the altered gene is 1 in
2 in each pregnancy for both boys and girls, but only the
male offspring will be affected. X- linked disease may thus
give rise to the disease in males in several different generations,
connected through the female line.
3.3.1.2
Polygenic disorders
Many
common diseases with a genetic basis result from abnormalities
in more than one gene. The inheritance pattern is complicated
because of the larger number of different genetic combinations
and uncertainties about how the genes interact. Environmental
factors frequently play a major part in such disorders, which
are more often known as multifactorial diseases. Because of
this, screening can yield results that are less clear-cut. At
the same time, as we advance our knowledge of all the environmental
and genetic factors involved, it will become possible to identify
individuals who are at increased risk of a disorder and who
would benefit from advice on how to minimise the risk. This
could lead to screening for genetic predisposition to common
diseases, such as coronary heart disease, diabetes and some
cancers.
3.3.1.3
Chromosomal disorders
Chromosomal
disorders fall into two broad categories.
- Where
an entire chromosome is added or is missing. For example,
in Down's syndrome there is an extra (third) copy of chromosome
21 found in the cells of affected individuals (hence the technical
term for it, Trisomy 21). In Turner's syndrome, one of the
X chromosomes in girls is missing. This type of disorder is
not inherited but occurs during the production of a gamete
(egg or sperm).
- Rearrangement
of chromosomal material. If this involves either net loss
or gain of chromosomal material, harmful clinical effects
are likely. On the other hand, if a simple exchange occurs
between chromosomes (translocation) or within them (inversion),
the chromosome make-up may be 'balanced', and serious clinical
effects are much less frequent.
3.3.1.4
Types of genetic tests
All
forms of genetic test aim to identify particular genetic characteristics
but approach this in different ways.
3.3.1.4.1
Chromosomal tests (cytogenetics)
Microscopic
examination of chromosomes from cells in blood, amniotic fluid
or fetal tissue may be used to detect the chromosomal changes
mentioned above. Until recent years it was possible to detect
only large alterations on a chromosome involving many genes,
but new techniques are making it possible to detect much smaller
defects, allowing recognition of disorders involving only a
small amount of genetic material.
3.3.1.4.2
Tests for disorders involving a single gene
Genes
cannot be seen through the light microscope, so tests for single
gene disorders have been largely indirect, involving what the
gene produces (protein), or another substance affected by it,
rather than the gene itself. The protein is still unknown for
the majority of genes, so testing for single gene disorders
has been very limited until recently.
3.3.1.4.3
Direct tests
Various
techniques have been developed for identifying important human
genes directly. The two main approaches are:
- the
gene may be isolated if the product (protein) it normally
produces is known. This approach was used for the genes involved
with the main blood cell protein, haemoglobin (important for
tests involving sickle cell disease and thalassaemia). The
genes causing some meta- bolic diseases, where a specific
chemical defect involving an enzyme was already known, have
also been isolated in this way;
- the
gene may be isolated if its position on a chromosome is known
(positional cloning). This approach is increasingly successful
in allowing genes to be isolated even when we know nothing
about their function or what protein they normally produce.
One reason for this success is that detailed genetic maps
of the different chromosomes are being produced. This approach
not only pinpoints the chromosome region where the gene lies,
but can provide genetic markers (identifiable pieces of DNA)
which lie close to the gene, and enables an accurate test
for a genetic disorder to be made even before the gene itself
is isolated.
Once the
gene responsible for a disorder has been isolated, it is possible
to study its different changes (mutations) that may result in
disease. These range from complete absence of the gene to faults
in a single chemical subunit of the gene. A single gene disorder
may be caused by many different changes in the gene responsible.
By careful study of particular populations of people it may
be possible to determine which mutations for a disease are the
commonest and most important, and to design a test programme
accordingly.
Direct genetic
testing by DNA techniques differs in several important respects
from most other forms of medical testing. Any body tissue can
be used since genes are present in almost all cells. Although
blood is most commonly used, cells obtained by mouthwash are
proving especially suitable for some screening programmes. Since
genes do not usually change during life, a DNA test can be performed
at any time from conception onwards. This is a practical advantage
for tests in early pregnancy, as it allows the detection of
a serious genetic abnormality that, otherwise, would not show
itself until after birth. However, this raises difficult ethical
problems, especially in relation to diseases that do not appear
until later childhood or adulthood.
Major scientific
advances have occurred in the sensitivity of genetic techniques,
allowing minute amounts of DNA or protein products to be analysed.
A particularly important advance has been the polymerase chain
reaction (PCR), which allows a single copy of a small part of
a gene to be amplified many thousand times. Testing of single
cells may make preconception testing of a single egg feasible,
and may also allow testing of fetal cells in the mother's blood
during early pregnancy. The dried blood spot taken onto filter
paper from all babies in the newborn period can be stored and
used for a wide range of genetic tests. New techniques increase
the potential impact of genetic testing, because they are often
suitable for mass population screening.
An important
discovery is that many stretches of normal DNA vary between
different people and together provide a pattern that is unique
for every individual (apart from identical twins). This powerful
technique, known as genetic fingerprinting, has many applications,
especially in legal cases. There are important ethical issues
as to when and how it should be used.
3.3.1.4.4
Indirect (biochemical) tests
These
tests do not detect the gene itself, but some aspect of its
function. The most nearly direct tests are for the specific
protein that the gene produces. In a genetic disorder, tests
may show that the protein is not being made or is present in
reduced amount; or that it may be altered so that it does not
function adequately. Such tests are important; for example,
for detecting abnormalities of haemoglobin (in thalassaemia
or sickle cell disease).
Where the
gene or its product cannot easily be tested, it may be possible
to measure some other substance that is altered in the disease.
Thus the screening test for the disorder phenylketonuria (PKU),
commonly used in Britain and South Africa on all newborn babies,
is based on measuring the amino acid, phenylalanine, which builds
up in the blood of affected persons.
3.3.1.4.5
Ultrasound
A
quite different but very important technique is ultrasound imaging,
which gives a virtually risk-free method of identifying structural
and some functional abnormalities that may result from genetic
disease. This technique is widely used during pregnancy for
the detection of fetal malformations, some of which are genetic
in origin. Some early manifestations of serious genetic disorders
that may develop in later life, such as polycystic kidney disease
(enlarged kidneys with cysts) or certain types of cardiomyopathy
(heart muscle disease) may also be detected.
3.3.2
Current screening programmes
In
reviewing existing screening programmes, some of which are well
established and others barely beyond the pilot stage, various
ethical problems may arise.
Screening
programmes are broadly divided into four groups, depending on
the timing of the testing. These are:
- neonatal
(in the newborn);
- older
children;
- testing
of couples or individuals before pregnancy (adults); and
- antenatal
(during pregnancy).
There may
be no single stage of life at which genetic screening is most
suitable. Screening may best be offered in a variety of ways,
and the optimal approach may change as the community becomes
better informed. For example, genetic screening for thalassaemia
in Cyprus and Sardinia (countries where this disorder is particularly
common) has progressed from the antenatal stage to the premarital
stage and towards screening in schools. This type of progression
may prove to be a common pattern as genetic screening becomes
a more established component of primary health care.
3.3.2.1
Neonatal screening
The
blood spot test for phenylketonuria (PKU) has not created any
major ethical problems. Likewise the test for congenital hypothyroidism,
which is carried out on the same sample, does not appear to
have raised any major ethical problems. This may be partly because
both diseases are severe and can be adequately treated if detected.
Nevertheless,
there is evidence that many women do not understand the purpose
of the test. A study in Britain of new mothers' knowledge of
the blood test for PKU and hypothyroidism, showed that two-thirds
said that the test had been fully explained. Most, in fact,
did not know what the test was for, and many incorrectly believed
that it also detected other disorders. Such results clearly
challenge any notion that women are giving informed consent
for their babies to be tested, although they believe themselves
to be informed. There is no reason to believe that South Africa
would be any different.
Some laboratories
carrying out neonatal screening for PKU and hypothyroidism,
in Britain and in other countries, have chosen to add tests
for other serious conditions. It is not always clear to what
extent parents are fully informed about these tests. A neonatal
screening programme in Pittsburgh, USA, has chosen to employ
'informed dissent', where parents are required to express a
wish to opt out if they so desire.
The present
method of screening for PKU, which is recessively inherited,
is indirect and does not identify the genes involved. If direct
gene testing were introduced, so that carriers as well as affected
individuals were identified, a different order of ethical issues
would arise. The finding of a carrier child has no disease implications
for the child, but may become important to that child in later
life, when reproductive decisions are being made. How and when
the child should be told would require careful consideration.
Neonatal
screening for sickle cell disease is cheap and reliable, and
it is recommended for populations with a significant incidence
of this disease. Early diagnosis of affected infants reduces
childhood mortality and morbidity, and allows parents to be
counselled about subsequent pregnancies. In some inner-city
areas in Britain, all newborns, regardless of ethnic origin,
are now screened for sickle cell disease. Screening, however,
does detect carriers as well as affected individuals, and thus
raises ethical issues for the families as discussed above.
Neonatal
screening for cystic fibrosis (CF) by indirect testing (for
trypsin in the blood) is carried out only in certain areas and
is still under evaluation. There is some, but not conclusive,
evidence that neonatal identification of infants with cystic
fibrosis may improve their prognosis, because preventive management
can be started before their lungs are damaged. Parents of affected
children can also be offered prenatal diagnosis in subsequent
pregnancies. DNA techniques, which identify carriers as well
as affected children, have been used for confirmation of the
diagnosis in the newborn period.
Pilot neonatal
screening programmes for early identification of Duchenne muscular
dystrophy have been set up in Britain (in Wales) and several
other countries. All of these programmes have been based on
an indirect method; the detection of the level of the enzyme,
creatine kinase, in the blood. These programmes vary somewhat
in detail, and in the manner of obtaining consent: the Pittsburgh
study, for example, employs informed dissent. The X-linked nature
of this disease raises particular ethical issues in terms of
implications for the extended family.
Because
neonatal screening for Duchenne muscular dystrophy is essentially
still in the pilot stage, evaluation of all the ethical issues
is not possible. Most workers involved consider that extensive,
well-monitored pilot phases should precede a decision on more
general implementations.
All newborn
babies have a physical examination which may detect congenital
disorders, some of which may have a genetic component. Examinations
are often carried out in the presence of the mother, and the
parents are informed about any abnormalities and their implications.
3.3.2.2
Later childhood screening
As
part of routine child health surveillance, all children have
a physical examination for a variety of diseases that may, in
part, have a genetic basis. For example, hearing defects may
be detected. Programmes of screening for specific genetic disorders
are in the pilot stage. These need to adhere to the principles
of informed consent (see 5.3 in Book 1).
3.3.2.3
Adult screening
Screening
of adults may be carried out to detect existing disease or predisposition
to a disease, or it may identify carriers with a reproductive
genetic risk. Most presymptomatic testing for late onset genetic
diseases (such as Huntington's disease) is currently offered
to family members at risk. Increasingly, general screening for
such late-onset genetic diseases is becoming technically feasible,
although not necessarily desirable.
Screening
programmes for various cancers that may have a genetic basis
are currently the main form of genetic screening in the adult
population. Testing the gene itself is now possible for familial
adenomatous polyposis, an inherited form of colorectal cancer.
It may soon be possible to screen a subgroup of women at high
risk of familial breast cancer, although at present such screening
is aimed at early detection of the cancer itself. These testing
programmes in families already known to be at risk, may be the
forerunners of future screening programmes.
The general
screening of individuals who may be carriers of inherited disease
genes is currently used only as a service to those in an ethnic
group known to have a high incidence of an inherited disease;
for example, the haemoglobin disorders in people of African,
Mediterranean and South East Asian origin and Tay-Sachs disease
in Ashkenazi Jews.
Pilot projects
have been undertaken in several centres in Britain to detect
carriers of cystic fibrosis in adults aged between 16 and 45
years through screening in general practice.
3.3.2.4
Pre-pregnancy and premarital screening
Testing
before pregnancy is not systematically practised to any extent
in Britain or South Africa. Screening for carriers of the haemoglobin
disorders may be offered through family planning clinics and
general practice. Insufficient information is available to evaluate
these programmes.
In Cyprus,
antenatal screening for thalassaemia has been almost totally
superseded by premarital screening. The religious authorities
had ethical objections to screening during pregnancy, on the
grounds that it excluded most options other than termination
of affected pregnancies. The church in Cyprus therefore insists
on testing as a formal prerequisite to church weddings. The
certificate required states merely that the partners have been
tested and appropriately advised. In this way the confidentiality
of the test result is preserved and the couple can exercise
an informed choice about reproduction.
General
population carrier-screening programmes for thalassaemia have
been established throughout the Mediterranean area. A comparative
study of these programmes has shown they are most rapidly and
equitably implemented when a small community at high risk is
served by motivated staff working from a single centre, with
the help of a lay support association (for example, Sardinia
and Cyprus). Such programmes have developed more slowly in larger
countries, as they must be delivered through the general health
care system, and staff must be trained to integrate screening
and counselling into routine services. It has proved particularly
difficult to organise carrier screening for haemoglobin disorders
where they are not a problem for the whole community, but primarily
affect ethnic minorities, as in Britain. This problem is the
subject of the Report of a Working Party of the Standing Medical
Advisory Committee on Sickle Cell, Thalassaemia and other Haemoglobinopathies.31
This report provides guidelines to health service purchasers
and providers on the provision of information, screening and
counselling services.
3.3.2.5
Screening during pregnancy
Screening
during pregnancy may be carried out on the mother, on the fetus,
or on both. If, through screening, a woman is found to be a
carrier of a gene for a recessive disorder, her partner may
be offered genetic testing to find out whether the couple is
at risk of having an affected child. If both parents carry the
gene for a recessive disorder, if the mother carries the gene
for an X-linked disorder, or if either parent has the gene for
a dominant disorder, tests may be done on the developing fetus.
There are several methods of obtaining samples for genetic tests
on the fetus, the most common being amniocentesis and chorionic
villus sampling (CVS). Genetic diagnosis can be achieved before
12 weeks' gestation with CVS, compared with about 16-20 weeks
by amniocentesis. However, the risk of miscarriage is slightly
higher for CVS (about 1-2% in excess of expectation at this
stage of pregnancy) than for amniocentesis (0.5-1%). The emotional
trauma caused by the need to consider a termination and to decide
whether or not to have one, must not be ignored. This is a major
ethical issue that applies to many screening procedures where
the disease is serious and where there is no effective treatment.
Informing parents of the reproductive choices, places a considerable
burden on them, and counselling and support will be needed -
whatever the decision.
In Britain,
antenatal screening tests are carried out on all women for a
predisposition to rhesus haemolytic disease of the newborn and
rubella (German measles). Rubella screening was the first screening
programme undertaken with the objective of offering detection
and abortion of potentially affected fetuses. Severe congenital
disorders may result from rubella infection during pregnancy.
Both rhesus and rubella screening appear to be well accepted.
Whereas the finding of a rhesus negative blood group results
in preventive treatment, a positive rubella test gives rise
to the need for very painful decisions, including the termination
of the pregnancy.
Ultrasound
scanning of the fetus is generally practised, and routine ultrasound
may reveal congenital abnormalities, some of which may have
a genetic basis. Expert fetal anomaly scanning, a specialised
form of ultrasound scanning, is offered to women known to be
at increased risk of having a malformed fetus because of genetic
or other reasons. In addition, it is increasingly offered to
all women on a routine basis, as about 70-80% of all severe
malformations can be detected by the technique. Although the
majority of women are aware of ultrasound, the amount of explanation
given regarding the possibility of detecting abnormalities varies
greatly, as does expertise in interpreting the results.
The offspring
of women with insulin-dependent diabetes mellitus have an increased
risk of stillbirth, neonatal ill health and major congenital
malformations, especially if their diabetes is poorly controlled.
In many women with diabetes the diagnosis will already be known,
but all women are screened early in pregnancy by blood and urine
tests to detect undiagnosed cases. Expert fetal anomaly scanning
by ultrasound is offered to all pregnant diabetics.
In many
areas, screening is carried out to detect neural tube defects
(spina bifida and anencephaly). Maternal serum alphafetoprotein
(AFP) determination is now offered routinely to all pregnant
women between 16 and 18 weeks of gestation, but in about half
of all pregnancies with a raised maternal serum AFP, no cause
can be found, either pre- or postnatally. A raised maternal
serum AFP normally leads to expert ultrasound examination for
a fetal malformation, with or without amniocentesis for confirmatory
biochemical tests.
Pilot studies
of screening during pregnancy for carriers of the common disorder,
cystic fibrosis, are currently being undertaken in a number
of centres in Britain, where 85- 90% of carriers can be detected
by a simple DNA screening test based on a mouthwash sample.
The various
studies of cystic fibrosis screening have devoted considerable
effort to the psychological and ethical issues surrounding genetic
screening programmes, especially since not all carriers can
be detected.
Antenatal
screening is offered to women in specific risk groups. All women
over an age that varies by area between 35 and 37 are offered
testing by chromosome studies for the presence of Down's syndrome
in the baby. Down's syndrome occurs in approximately 1 in 600
of all births; but is much less common in children born to younger
women (1 in 1 500 at age 20). Its birth incidence increases
with maternal age, being about 1 in 350 at age 35, and as high
as 1 in 100 at age 40. Recently, maternal serum screening tests
have been developed that can be offered to all pregnant women,
regardless of age, to detect those who may be at increased risk
of having a child with Down's syndrome, in order to offer the
choice of amniocentesis and chromosome testing. Unfortunately,
only just over 60% of affected babies will be detected in this
way and 5% of the screened pregnancies will give results necessitating
an amniocentesis, to reassure the participating women that they
are not carrying a fetus with Down's syndrome.
3.3.2.6
Practice implications
Health
professionals must recognise women's fears that the unborn baby
might have a serious abnormality and their need for information
about the implications where such a diagnosis is confirmed.
Further, protocols concerning the implementation of screening
programmes should include adequate psychosocial support for
participants.
3.3.3
Counselling, providing information and obtaining consent
Genetic
counselling is the provision of accurate, full and unbiased
information that individuals and families require to make decisions
in an empathetic relationship that offers guidance and assists
people to work towards their own decisions.32 The
information should include a full description of the risks,
diagnosis, symptoms and treatment of the disorder in question.
Information about financial costs, emotional costs, education,
and both positive and negative effects on the marriage and family
unit should be included, as well as available social and financial
supports for persons with genetic conditions.14
It is fundamental
that actual knowledge or understanding on the part of the patient,
or person consenting on behalf of the patient, is achieved.
It is not sufficient for the practitioner to have reasonably
explained the information. Informed consent is valid only when
it represents true understanding.14 This rigorous
test of consent is linked to the patients' right to be so informed
that they understand the proposed test or procedure, the possible
alternatives and any associated risks, to enable them to make
a balanced judgement on whether to continue with the test or
procedure or to withdraw.14 Evidence suggests that
the combination of written information supplemented with face-to-face
interaction is the most desirable method of ensuring that patients
receive sufficient information to empower them to make this
choice.26 It must be clear at all stages of the screening
that the participant or patient is free to withdraw from the
process at any time (see 5.3 in Book 1).
It is recommended
that the following ethical principles should be applied to genetic
counselling:
- respect
for persons, families and their decisions according to the
principles underlying informed consent;
- preservation
of family integrity;
- full
disclosure to individuals and families, of accurate, unbiased
information relevant to health;
- protection
of the privacy of individuals and families from unjustified
intrusions by employers, insurers and schools;
- informing
families and individuals about possible misuses of genetic
information by institutional third parties;
- informing
individuals that it is their ethical duty to tell blood relatives
of the genetic risks to which they may be exposed;
- informing
individuals about the wisdom of disclosing their carrier status
to a spouse or partner if children are intended, and the possibility
of harmful effects on the marriage from non-disclosure;
- informing
people of their moral duty to disclose a genetic status that
may affect public safety;
- unbiased
presentation of information, insofar as this is possible;
- adopting
a non-directive approach, except when treatment is available,
although the person being counselled may still decline treatment;
- involving
children and adolescents whenever possible, in decisions affecting
them; and
- observing
the duty to re-contact if appropriate and desired.32
Informed
consent is an accepted norm in the clinician-patient relationship,
implying the patients' knowledge of the major characteristics
of their medical disorder, an understanding of the test or procedure
they are to undergo, the limitations of the test or procedure,
and the possible consequence of their participation in the test
or procedure followed by their agreement, or not, to undergo
the test or procedure.14 This term includes a right
on the part of the participants or patients to be informed of
risks not actually related to the medical impact of the test
or procedure, including:
"Possible
socio-economic consequences of an unfavourable test result,
such as loss of health or life insurance, refusal of employment,
discrimination by schools, adoption agencies etc. should where
applicable, be included under the description of risks."14
It is recommended,
further, that information to be given to any patient undergoing
genetic screening should include:
- the
seriousness of the condition to which the genetic disorder
may give rise and how variable its effects are;
- the
therapeutic options available;
- how
the disorder is transmitted, the significance of carrier status
and the probability of development of the serious genetic
disease;
- the
reliability of the screening procedure and the results of
the test;
- information
detailing how the results of the screening test will be passed
on to the patient, and what will be done with the samples;
- the
implications of a positive result for their future and existing
children and for other family members;
- a warning
that the screening test may reveal unexpected and awkward
information; for example, about paternity.26
3.3.4
Genetic screening - the law and public policy
The
negative impacts of genetic screening may be separated into
two categories of harm. The first is the effect on the personal
choices and mental well being of the individual, and the second
is the effect on the interaction of that individual with society
at large. The first category of harm may include increased personal
anxiety about health, decisions related to the termination of
pregnancy, and deciding whether to pass on genetic information
to spouses, partners or family members.26 The second
category involves more powerful ethical considerations with
regard to eugenics, employment prospects and access to life
insurance and other benefits. It is with this second-category
harm that we are primarily concerned in these guidelines.
3.3.4.1
Results of genetic screening and confidentiality
Genetic
information can be effectively used to reduce the health-related
cost of labour. This simple fact is the most powerful reason
for employers and insurers to be interested in genetic screening
and testing. On the other hand, the dissemination of genetic
information to employers and insurers may be linked to the dangers
of "isolation, loss of insurance, educational and job opportunities
for persons diagnosed with incurable and costly disorders."
28
Dangers
associated with genetic screening differ from those associated
with genetic testing. Genetic screening is carried out at the
instance of the State or large institutions, while genetic testing
is done at the instance of the individual being tested. Guidelines
related to genetic screening should also govern the scope and
aim of screening programmes and ethical aspects relating to
the use, storage and registration of data and follow-up procedure,28
while guidelines for genetic testing should be more focused
on aspects pertaining to the individual and the protection of
his or her rights.
3.3.4.1.1
The scope and aim of screening programmes
"The
literature on genetic screening and discrimination suggests
several areas of sensitivity:
- the
workplace, where employers may choose to test job applicants,
or those already employed, for susceptibility to toxic substances
or for genetic variations that could lead to future disabilities,
thereby raising health or compensation costs. In terms of
Section 7 of the Employment Equity Act, No. 55 of 1998, medical
testing of employees or job applicants by employers is prohibited
in South Africa unless legislation permits or requires testing,
or it is justified in the light of medical facts, employment
conditions, social policy, the fair distribution of employee
benefits or the inherent requirements of a job. Medical testing
includes any test, question, inquiry or other means designed
to ascertain, or which has the effect of enabling the employer
to ascertain, whether an employee has any medical condition.
Medical testing could therefore include some types of genetic
testing;
- the
insurers (either life or health insurance companies) who might
use genetic information or tests as criteria for denying coverage
or require reproductive testing to be done for cost containment
purposes. In terms of the South African Medical Schemes Act
No. 131 of 1998, a registered medical aid scheme may not unfairly
discriminate directly or indirectly against its members on
the basis of their "state of health"; and,
- law
enforcement officials, who may test and/or use information
without informed consent."28
It is trite
to state that employers and insurers should have limited rights
to initiate screening programmes. This alone will not prevent
genetic discrimination from occurring for so long as employers
and insurers have access to genetic information.j
3.3.4.1.2
Test results, privacy and data protection
Every
individual undergoing either genetic screening or genetic testing
has the right to be fully informed of the results concerning
a suspected disorder.26 A difficulty arises where
an individual is to be informed of results that are "unexpected,
unwanted, and have not been covered by consent. For example,
a sex chromosome abnormality may be revealed when carrying out
prenatal testing for Down's syndrome, or a different inherited
disease may show up on a test designed for another purpose.
Unexpected information can present ethical dilemmas for which
there are no easy answers, or indeed correct answers."26
Article
8(l) of the European Convention on Human Rights provides that
'Everyone has the right to respect for his private and family
life, his home and his correspondence'. The right to private
life, or to privacy, clearly includes the right to be protected
from the unwanted publication or disclosure of intimate personal
information. The South African Constitution clearly protects
each individual's right to privacy. Section 14 of the Constitution
and the common-law right to privacy include privacy of information;
that is, the right to determine for oneself how and to what
extent information about oneself is communicated to others.
These general
principles are particularly important in medicine. Respect for
privacy is vital to the clinician/patient relationship. The
relationship must be built on trust and confidence if patients
are to reveal information essential to the proper diagnosis
and treatment of their condition. Yet trust and confidence would
soon be shattered if clinicians were to fail to respect the
confidentiality of intimate personal information.
The case
for confidentiality in medicine applies with equal force to
genetic screening. Individuals agreeing to be screened need
to be confident that no results will be made available to anyone
other than themselves and their medical advisers, without their
explicit consent. Otherwise, people may be reluctant to participate,
perhaps with damaging implications for themselves, their families
and, potentially, other third parties. If clinicians were to
break the confidence relating to genetic information, there
would be adverse implications for other areas relating to the
care and treatment of the patient. The patient would fear that
other medical information was being disclosed to a third party.
The rights
to privacy generally, and to the confidentiality of personal
medical information in particular, are of the greatest importance,
but it does not necessarily follow that both should be wholly
unqualified. Article 8(2) of the European Convention on Human
Rights provides, for example, that the individual's right to
personal privacy may be overridden by requirements prescribed
by laws introduced to protect health, morals, or the rights
and freedoms of others. Section 36 of the South African Constitution
also provides for the limitation of rights by laws of general
application, to the extent that the limitation is reasonable
and justifiable in an open and democratic society, taking into
account various factors. These provisions may be particularly
important in genetic screening.
The decision
of an individual to participate in a genetic screening or testing
programme may have implications for other family members, which
could affect their future. The question is whether there is
an obligation on the part of health professionals to consider
the interests of the family members, even if the participating
individual does not wish to warn relatives who might be at risk.
The HUGO Ethics Committee in a statement on DNA Sampling: Control
and Access, states that the "shared biological risks [of
family members] create special interests and moral obligations
with respect to access, storage and destruction that may occasionally
outweigh individual wishes."33
The issue
is a contentious one, because the claims of family members may
vary in strength. An individual may have an interest in knowing
whether a partner or prospective partner is likely to suffer
from, for instance, familial colon or breast cancer, or Huntington's
disease. But such an interest, while understandable, falls far
short of any right to demand knowledge. The emphasis is somewhat
different if having children with a particular partner is contemplated.
For example, a pregnant woman may legitimately want to know
the result of the screening test on the father of her child,
if she herself has had a positive test, indicating that she
carries a gene for cystic fibrosis or Tay-Sachs disease. A different
problem may arise with blood relatives, where non-disclosure
of information might lead to an unnecessary termination, or
where a relative, not informed of a high genetic risk, might
become the parent of a child with a serious genetic disorder.
A more difficult case is made out for siblings and other blood
relatives who face the same risks in respect of a genetic disorder
or disease, and may well have an interest in the outcome of
the screening results.
3.3.4.1.3
The ethical dilemmas
We
discuss first the responsibility of the individual in resolving
the dilemmas, and next, the role and responsibility of the clinician
or other professional adviser. The main ethical dilemma arises
from a conflict between the right of the individual to personal
privacy, and the reasonable desire of family members to be fully
informed. The information, after all, might play a part in important
decisions about their lives. A balance needs to be struck between
the two. A further complicating factor, though, is that some
family members may prefer not to be presented with the information.
This would become a much more serious problem if widespread
screening were introduced for X-linked or autosomal dominant
diseases.
The individual's
responsibility
The
question of responsibility has at least two dimensions here.
The first is the responsibility of the individual to pass on
relevant information to other family members, and the second
is the responsibility of the other family members to receive
the information. We adopt the view that a person acting responsibly
would normally wish to communicate important genetic information
to other family members. These members may have an interest
in the information, and a responsible person would probably
wish to receive it, particularly where it might have a bearing
on decisions that he or she may take in the future. We are also
of the view that the primary responsibility for communicating
genetic information to a family member or other third party
lies with the individual and not with the clinician, who may,
however, do this at the request of the person concerned.
Where family
members do not wish to know, the situation may be more difficult.
If family members were unaware that a relative had been screened,
they would not know whether or not they wanted to be informed
about the result. In these circumstances the individual who
had been tested might have to inform them - or not inform them
- personally.
Although
serious problems may arise as a result of non-disclosure, and
certain family members may have a legitimate interest in the
information, this should not always supersede the individual's
right to privacy. It is difficult to contemplate how any such
legal obligation would apply, and how any legal right of family
members (assuming that they could be identified) could be enforced.
South African law does not impose a general duty to inform,
but the community values (boni mores) may demand disclosure,
to inform potentially identifiable persons within easy reach,
who might suffer serious harm.k In any event, in certain circumstances
there may be perfectly good reasons why an individual would
not wish to inform family members about the result of a genetic
test. For example, a woman who has discovered she is a carrier
of Duchenne muscular dystrophy may not wish to tell her sister
who is 7 months pregnant.
The best
way to ensure that genetic findings are appropriately shared
with family members (and occasionally with other third parties)
is through information and counselling procedures. Disclosure
to other family members ought not to be made a condition of
participation in a screening programme. Inevitably some individuals
will refuse to allow disclosure and this may present the clinician
or other health professional with an ethical dilemma.
The clinician's
dilemma
Just
as we have rejected the suggestion that there should be a legally
enforceable duty placed on people who have been screened, to
inform family members or other third parties of the results,
so too we reject the idea that clinicians should be placed under
a legal duty to reveal information against the wishes of the
individual concerned. No such general duty is acknowledged by
law in this country, although the position may be different
elsewhere. The furthest the law appears to go is to recognise
that in exceptional and ill-defined cases the clinician may
have discretion to disclose genetic information to third parties
(see 3.3.4.1.2).
Privacy
and confidentiality should be respected and maintained, but
we also accept that there may be exceptional circumstances in
which these might properly be overridden by the clinician; for
example, where information is withheld out of malice. We do
not suggest that the wishes of the individual should be overridden
only in this type of case. However, it illustrates how exceptional
are the situations in which it may be appropriate and reasonable
to subordinate the individual's privacy to the interests of
others.
It is impossible
to foresee all the circumstances in which a doctor might properly
disclose confidential information to family members. Although
a set of guidelines and a knowledge of the law may be helpful,
the decision on disclosure is also made according to the facts
of each case. See in this respect the ethical guidelines of
the South African Medical Association on HIV/AIDS (1998) and
those of the Health Professions Council of South Africa (1994),
which make provision for disclosure of a patient's HIV status.
This imposes
a heavy burden of responsibility on the health professional.
Two factors stand out as especially relevant. The first is the
consequence of the refusal to share information. There would
be a stronger case for overriding individuals' objections where
consequences of disclosure are potentially damaging, rather
than merely inconvenient to other family members. The second
factor is the reason for the individual's refusal to permit
disclosure. If it can be determined that the reasons are malicious,
the decision may be straightforward. However, if the reason
was a fear that the information might yield compromising evidence
about paternity, the ethical issues would be quite different.
If information about non-paternity was not disclosed, a man
who incorrectly believed himself to be the father of a child
with a particular genetic status might make the wrong decisions
about having other children. On the other hand, for the health
professional to reveal such information might lead to harm to
the woman concerned, not only because of the breach of confidentiality
itself, but also because of its impact on the woman's relationship
with the man involved. For this dilemma there is no easy answer.
It is recommended,
therefore, that the following points be adopted as guidelines
to disclosure, to families, of the results of a genetic screening
programme:
- "the
accepted standards of the confidentiality of medical information
should be followed as far as possible;
- where
the application of such standards might result in grave damage
to the interests of other family members, the health professional
should seek to persuade the individual to allow disclosure
of the genetic information. The potential seriousness of non-disclosure
should be explained to the individual;
- in exceptional
circumstances, health professionals might be justified in
disclosing genetic information to other family members, despite
an individual's desire for confidentiality."26
3.3.4.1.4
Genetic registers
In
the context of genetic screening, where large numbers of tests
are undertaken, this may be recorded in the form of a genetic
register or similar database. Special consideration should be
given to the implications for security of these grouped results.
A register
may be defined as a systematic collection of relevant information
on a group of individuals. Genetic registers record information
on individuals with specific genetic disorders, and may include
relatives at risk of developing or transmitting the condition.
The information may be recorded by hand, or may be held on computer.
Genetic registers may be set up for a variety of reasons, including
research on the disorder, the effective provision of services
to those on the register, and the systematic offer of genetic
counselling to family members. The amount and type of information
recorded varies greatly, as does the presence of identifying
details.
There are
several general ethical issues concerning genetic registers.
Here we outline issues relating to genetic screening. They should
be seen against the background of the following points:
- a genetic
register may be the starting point for genetic screening;
for example, the systematic testing of relatives of individuals
with fragile X syndrome or Duchenne muscular dystrophy;
- genetic
screening may also be based on a register not specifically
genetic in its basis; for example, registers of specific cancers
or of those with severe learning difficulties;
- a genetic
register may be the product of a genetic screening programme;
for example, a register of carriers of cystic fibrosis or
sickle cell disease in a population screened for the purpose.
It is essential
to obtain individuals' consent before placing their names on
a register. It is also important that individuals know that
they are on the register, and what use will be made of the information.
Consent
of individuals to long-term storage of information resulting
from genetic screening has been emphasised earlier. However,
if this is to form the foundation of a genetic register, separate
and specific consent should be sought for subsequent tests or
other measures, also for further use which may generate financial
benefits for the investigator.
Confidentiality
of all medical information is essential, and this is particularly
the case with genetic registers, which may contain highly sensitive
and potentially identifiable data on large numbers of individuals
with, or at risk of, serious genetic disorders.
Computer-based
genetic registers are subject to the Promotion of Access to
Information Act, No. 2 of 2000, but there is need for additional
safeguards for all genetic registers, including secure storage
of information, limitation of access to those specifically responsible
for a register, and the removal of identifying information when
data are used for research purposes. Further, a Data Protection
Act is envisaged for South Africa.
This is
an important area of concern. The Department of Health, in consultation
with health authorities and appropriate professional bodies,
should devise effective arrangements for the preservation of
confidentiality, particularly in relation to genetic registers,
and should provide the necessary guidance.
3.3.4.2
Employment
Competition
drives the players in the economy to reduce costs and increase
efficiency. In the context of employment, genetic screening
provides the employer with an opportunity to reduce the health-related
costs of employment. An employer may want to screen candidates,
to exclude those susceptible to either occupational or non-
occupational disease.
"Healthy
workers cost less: they are less often absent through illness,
there are lower costs for hiring temporary replacements or for
training permanent replacements, and there are fewer precautions
which would need to be taken to deal with health and safety
risks."26
The dangers
of permitting employers to embark on their own screening programmes
are self evident. The result would be restrictions on the employment
of individuals who are at risk of genetic disease, and the creation
of class orders based on genetic disposition. In other words,
genetic discrimination would ensue. Wealth most often follows
employment, education follows wealth, and employment follows
education: a neat circle ensuring comfort for those within its
exclusive confines. The cost implications for the State are
critical. Whereas the business community currently bears some
of the costs of genetic disease in the population, by excluding
this cost through genetic screening, business would effectively
shift the their share of the cost to the State, with repercussions
for social welfare and health policy in particular.
However,
employees and the public at large have an interest in reducing
the incidence of occupational disease. It is accepted that employers
may require employees to undergo screening for illnesses or
conditions that present a serious danger to third parties.26
Thus genetic screening may have a limited role to play in employment.
One way of achieving this is for the State to introduce screening
programmes whereby individuals are made aware of their genetic
disposition and are empowered to make informed decisions with
regard to their employment and their health.
Section
7 of the Employment Equity Act. No. 55 of 1998, prohibits the
medical testing of employees and applicants for employment,
unless legislation permits or requires testing, or it is justifiable
in the light of various factors, such as employment conditions
or the inherent requirements of the job.
3.3.4.3
Insurance
Insurance
and risk management are two separate forms of practice. Risk
management seeks to reduce the costs associated with risks that
will certainly eventuate, whereas insurance is more like a gamble:
it is unknown whether the event will occur or not. The relevance
of this to genetic screening is that at present the medical
aid industry operates as a form of insurance. Insurers constantly
try to determine the risk associated with potential clients,
to better allocate the premiums and so attract the least risky
clients.
The revolution
in genetics allows insurers to reduce uncertainty about future
events. This fundamentally changes the context of insurance.
The more predicable the risk, the more accurately an insurer
can apportion premiums. The repercussions for individuals with
genetic predispositions to certain diseases are that they may
not be granted health insurance at all, or may be charged higher
premiums. It has to be borne in mind that The Medical Schemes
Act, No. 131 of 1998, provides that a registered medical aid
scheme may not unfairly discriminate directly or indirectly
against its members on the basis of their 'state of health'.
However,
insurers have argued that using genetic information to predict
risks is nothing more radical than an extension of their current
practice. At present, insurers require people seeking insurance
to provide information regarding their family medical history
and lifestyle, to be able to predict the risks and thereby to
determine an appropriate premium. Further, insurers require
insurance applicants to disclose all known information that
would impact on the risk - this would include disclosure of
both an HIV positive status and the results of genetic tests.
It is thus argued that the additional information obtained from
genetic tests is an extension of accepted practices.
At face
value, the argument is persuasive. However, the results of genetic
tests do not always predict outcomes, but are rather a test
for a certain mutation.
"Additional
statistical information linking a given test result to the occurrence
of some disorder is also needed if a sound prediction of disease
or of lowered life expectation is to be made on the basis of
a genetic test result. Without information that links genetic
test results to incidence of disease or death, they lack actuarial
import."34
There is
information linking the existence of certain single gene disorders
to the onset of a genetic disease or lowered life expectancy.
However, it is not clear whether the relevant test predicts
the onset of the disease or establishes the presence of the
disease.34 Insurers require predictive test results,
but even those predictive tests that are available cannot accurately
determine the onset of the genetic disease.
Recommendations
on the use of genetic screening and genetic tests by insurance
companies arise from the following considerations:
- the
difficulty of assessing sometimes slender evidence on the
genetic susceptibility of individuals to develop polygenic
and multi-factorial diseases (for example, some cancers and
some forms of heart disease);
- an awareness
that ordinary commercial practice will lead companies to be
overcautious in their assessment of the risks derived from
medical data; and
- the
possibility of abuses.
3.3.4.4
Children
There
are well-founded reasons for testing asymptomatic children and
adolescents for genetic diseases or carrier status. However,
genetic testing of children raises ethical concerns over issues
such as informed consent and disclosure to the child. The test
is conducted only where it is in the best interests of the child;
thus the primary justification for the test should be timely
medical benefit to the child.35 If the provider of
the test is of the view that the potential harm of the test
would outweigh the potential benefit, or if medical intervention
would be of no benefit until adulthood, the test should be deferred
until adulthood.35
There is
a presumption of parental authority in our law, which acknowledges
the child's lack of the capacity to make appropriate life-impacting
decisions, and that parents are usually best placed to decide
about the well-being of their child, and have the greatest interest
in promoting their children's well-being.35 The assent
of the child should be sought. Related to this right is the
right to make an informed decision without interference from
health-care providers, although this right can be limited where
there are objective reasons to believe that a decision or action
has significant potential for an adverse impact on the health
or well-being of the child.35
The following
recommendations of The American Society of Human Genetics and
the American College of Medical Genetics Report35
in respect of family involvement in decision-making are endorsed:
-
education and counselling for the parents and the child, according
to the child's maturity, should precede genetic testing;
- the
test provider should obtain the permission of the parents
and the assent of the child or the consent of the adolescent.
In terms of the Child Care Act, No. 74 of 1983, a child above
the age of 14 years may consent independently to medical treatment,
which would include genetic testing from which the child could
benefit directly (see 5.3, Book 1);
- the
test provider is obliged to advocate the child's best interests
at all times;
- a request
by a competent adolescent for the results of a genetic test
should be given priority over the parents' requests to withhold
information.
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