GENETIC INTERVENTION
Genetic Reconstruction/Genetic Engineering:
This is the effort to repair genetic defects at their
genotypic source in the genes and chromosomes
rather than in their phenotypic effects and, further, to
control and produce at will new combinations of
genetic traits in offspring.
1.
Sexual Selection:
To determine the sex of the fetus by selecting
sperm that do or do not have the Y chromosome
that determines maleness and then using selected
sperm for artificial insemination or in vitro
fertilization and implantation.
2.
Splicing genes and influencing the genotype of
lower forms of life, must also be subjected to the
same ethical norms as other research protocols.
3.
Superior Human Beings:
Recombine genes in the nucleus of a zygote,
probably by using viruses that can incorporate a
section of a chromosome derived from one
nucleus and fixing it in a chromosome of another
(transduction).
Unethical, on the grounds that it would be
usurpation of God’s creative power (principle of
stewardship).
(1)
HUMAN GENE THERAPY AND GENETIC
ENGINEERING
Types of Genetic Intervention:
Cure of disease
somatic cells
germ-line cells
Enhancement
of capabilities
1
3
2
4
____________________
I. Cure of Disease:
Type 1 - aims to cure a condition that is generally
acknowledged to be a disease by genetically
altering the non-reproductive cells of a patient.
Done thru “bone marrow transplantation with an
extra step.”
Examples of diseases that can possibly be cured:
1) the bone-marrow cells of a patient suffering from
sickle cell anemia may be able to be treated and the
patient cured of his or her disease. However, this
cure would not be transmitted to the patient’s
descendant.
2) adenosine deaminase (ADA) deficiency, which causes
the total collapse of children’s immune systems.
Type 2 - both somatic (nonreproductive) and reproductive
cells would be treated, so that the changes of the
genetic “cure” would be passed on to the patient’s
descendant. (Depending on the type of genetic alteration
and the stage of development at which it were performed, it is
possible that only some of the patient’s descendants would be
cured.) Studies of this have been done in mice.
(2)
II.
Enhancement of capabilities:
Type 3 - doubling the efficiency of an individual’s
long-term memory based on somatic
cells alterations.
Type 4 - if enhancement of individual’s long-term
memory is based on both the somatic &
reproductive cells, the long-term memory
efficiency would also be passed on to at
least some of the subject’s descendants.
APPLICATION OF ETHICAL THEORIES
Pope John Paul II
“a strictly therapeutic
intervention whose explicit objective is the healing of
various maladies such as those stemming from
chromosomal defects will, in principle, be considered
desirable, provided it is directed to the true promotion
of the personal well-being of the individual without
doing harm to his integrity or worsening his
conditions of life. Such intervention would indeed fall
within the logic of the Christian moral tradition.”
(3)
ETHICAL CONSIDERATIONS
Type 1 -
proposed for use with human patients.
Technique will be qualitatively similar to other
biochemical innovations, like kidney
transplants.
Type 2 -
the probable benefit/harm ratio is not
Proportional to Possible benefits (rationale):
a)
b)
cells in some parts of the body can only be
reached and effectively treated if gene
therapy
is
administered
very
early
(embryonic stage of development). This can
treat otherwise unreachable brain cells, thus
preventing the brain-based disease from
occurring in the future person.
Principle of efficiency: - it is more reasonable
to correct a defect once, through germ-line
gene therapy, and to have that correction
passed on to the subject’s descendants than
to repeat somatic-cell gene therapy,
generation after generation, in a family
afflicted by a genetic disease. (Only some of
the subject’s descendants would receive the
properly-functioning added gene, while
others would receive only the malfunctioning
gene).
(4)
Possible risks:
a)
b)
c)
d)
e)
Major obstacle is technical. Large majority of
embryos into which added DNA is
microinjected, either do not survive the
injection procedure, do not implant, do not
survive because of a new lethal mutation, or
do not express the added gene or genes.
Therapeutic
interventions
during
the
embryonic stage, one would not know in
most cases whether a particular embryo
were destined to be afflicted with a genetic
disease.
the “touch down” of the retroviral vectors is
not possible to control. Vectors may disrupt
properly-functioning genes and therefore kill
some cells;
vectors may activate some previously
dormant cancer-causing genes;
the domesticated retroviral vectors may
recombine with other DNA or other viruses
and so recapture their native capacity to
produce more retroviruses and to infect large
number of cells;
(5)
Types 3 & 4 - Ethically unacceptable
a)
b)
c)
d)
a manifestation of hubris (an attempt to
play God).
Such a program would inevitably lead to
eugenics, an attempt by society to coerce
everyone to participate in the genetic
improvement program.
Such a program would be utopian; it
would attempt to develop a perfect
human being or a perfect society.
Different culture have different ideals and
that therefore human beings would not be
able to agree on which traits are better or
worse for them.
GENETIC INTERVENTION:
1.
2.
3.
Genetic therapy
Genetic surgery
Genetic splicing
To use human embryos or fetuses as the object or
instrument of experimentation constitutes a crime
against their dignity as human beings having a right
to the same respect that is due to the child already
born and to every human person. (Shannon 1987: 599600).
(6)
GENETIC SCREENING:
GENETIC CONTROL:
PRENATAL DIAGNOSIS:
IN VITRO FERTILIZATION:
EMBRYO TRANSFER:
CLONING:
It is done with the purpose
of aborting the fetus if it is
found to be deformed,
hence, it is to be condemned
as a violation of the unborn
child’s right to life.
Constitute an offense
against the
respect due to human
beings by
manipulating them.
SURROGACY: - contrary to the unity of marriage and
to the dignity of the procreation of the
human person.
SPLICING GENES - and influencing the genotype of
lower forms of life must also be
subjected to the same ethical norms as
other research protocols.
SUPERIOR HUMAN BEINGS:
Recombine genes in the nucleus of a zygote,
probably by using viruses that can incorporate a
section of a chromosome derived from one nucleus
and fixing it in a chromosome of another
(transduction).
Unethical, on the grounds that it would be
usurpation of God’s creative power. (principle of
stewardship).
(7)
CONCLUSIONS
1.
It is more feasible, technically and ethically, to
improve the human condition by improving the
environment and development of the individual, that
is, the phenotype, than by modifying genetic
endowment, that is the genotype, and priority in
research and investment of medical resources should
be given to the former effort. Genetic research is
extremely important, however, to understand the
interactions of genotype and phenotype.
2.
Presently proposed methods of genetic reconstruction
of human beings involve in vitro fertilization and other
procedures that are ethically objectionable because
they separate reproduction from its parental context
and involve the production of human beings, of whom
some will be defective because of experimental failure
and who will probably be destroyed. This contravenes
the basic principles of ethical experimentation with
human subjects.
3.
Proposals to improve the human race by sex
selection, cloning, or genetic reconstruction are
ethically unacceptable in the present state of
knowledge. Unless limited to very modest
interventions, they would restrict the genetic variability
important to human survival, and they would separate
reproduction from its parental context.
(8)
4.
If the foregoing problems can be overcome, it will be
ethically desirable to develop and use genetic methods
for therapy of genetic defects in existing embryos,
keeping in view the risk-benefit proportion.
The principle of stewardship throws light on many of
the problems of human reconstruction. Natural law should
not be conceived of as a fixed pattern of human life to which
human beings are forever confined. Rather, the Creator has
made human beings free and intelligent, and it is precisely
this intelligent freedom that is human nature and the
foundation of natural moral law. Human intelligence,
however, is not disembodied but depends on a brain and a
body that have a specific structure. In caring for their total
health, persons not only have the right but the obligation to
understand their psychological and biological structure and
to improve themselves even in ways that may seem novel to
past generations. Such improvement is good stewardship of
the share in divine creativity with which God has endowed
mankind.
In particular, Christians should be concerned that such
innovations do not weaken the fundamental relations within
the family or the sense of the child as a unique gift of God.
At the same time, persons must use this creativity with
profound respect for God’s existing creation and especially
for their own psychological and biological mode of
existence, lest by tampering with their brains or the rest of
their personalities they should undermine the freedom and
intelligence on which this creativity depends (principle of
totality). Consequently, the use of surgery and genetic
manipulation to improve their bodies is ethically good,
provided that they take full account of such risks and are not
carried away by a false ambition to work technical miracles
without regard to their real meaning for human living. (9)
ETHICAL and PUBLIC POLICY ISSUES
1.
2.
3.
4.
Freedom and coercion in genetic testing and
screening
Confidentiality or disclosure of test results
Access to genetic testing services
Probable benefits and harms of genetic
testing and screening programs
Freedom and Coercion:
“ethics of genetic duty” – individuals and couples
have a moral duty to learn what they can about the
likelihood that they will transmit genetic conditions to
their offspring and to take steps that are compatible
with their other ethical convictions to avoid causing
preventable harm to their descendants.
Confidentiality and Disclosure:
Who, besides the individual and his or her health
provider, should have the access to the information
about the genetic condition?
Two contexts:
1. Extended family context –
Individuals or couple who learn that they
have genetic disease or carry a genetic trait
may face decisions about whether to inform
their parents, their siblings, their children,
and even more distant relatives.
(10)
2.
Business context
involve either employers or insurers. “the
potential for misuse as well as unintended
social or economic injury, information about
genetic conditions should be disclosed to
insurers or employers only with the explicit
consent of the person tested”.
POSSIBLE BENEFITS AND HARMS:
A.
Principal benefits:
1. knowledge
2. the ability to avoid transmitting genetic
disease to offspring
3. the ability to secure timely treatment for a
genetic condition.
4. may help to “democratize” genetic disease
- it may become clearer that visible and
invisible genetic problems are simply an
omnipresent aspect of the human condition
B.
Possible harms:
1. through coercion
2. through leading to exclusion from the work
force or the health care system
3. through providing incomplete information or
partial services.
4. a positive genetic test may result in the
stigmatization of the individual tested.
(11)