Every human society
requires that its future generation be healthy. This depends
on the birth and rearing of healthy children. To this end,
preventive screening for genetic disorders, including developmental
disabilities, is an essential component in uncovering possible
disorders early, thus enabling timely medical intervention.
Such efforts are also required in order to reduce the expression
and severity of disability. The ability of a physically or
mentally disabled child to cope with and adapt to everyday
life may be minimal compared to that of a normal child, and
the disabled child may continuously suffer from trying to
perform the functions so normal to others. This can have a
major influence on the personality of the child which in turn
can affect normal growth and development. Of particular distress
is the fact that some disabled children never reach adulthood
and some are at risk of developing other associated complications
which may further disrupt their social and emotional development.
These children and their families are under continuous mental
and physical stress and require comprehensive services in
order to help the children have a near normal life.
In addition, many disabled people require a continuous health
care system, home help and other supportive services, which
makes care programs very costly. The management of childhood
disabilities requires substantial medical, educational, social
and rehabilitative care. The cost of preventive efforts is
substantially lower and thus cost-effectiveness favors the
prevention approach.
Stages of Prevention
Endeavors for controlling disability can be categorized
as primary, secondary and tertiary prevention.
- Primary Prevention This
involves the prevention of the manifestation of the disability.
It may be universal (i.e. prevention desirable for everyone),
or be restricted to a selected population (ie, prevention
recommended for high-risk groups) or to an indicated population
(i.e. prevention in individuals with an identified risk).
Primary efforts are directed toward reducing the actual
occurrence of disabilities and they employ measures that
prevent the conception of a disabled individual or delay
the disabling process. Primary prevention efforts include:
- Genetic Counseling
Genetic counseling is an essential part of primary
prevention strategies. It is the process of providing
information on genetic (recurrence) risk, the nature
and consequence of genetic disorders and the means
available for the prevention of transmission of defective
genes. Within this framework, there are three major
aspects essential to effective counseling which are:
- diagnostic aspects, where an accurate diagnosis
is required for a secure foundation for advice
- estimation of risk
- preventive or ameliorative measures to ensure
that those who are advised will benefit
One of the prime requirements of an effective genetic
counseling program is to ascertain which individuals
are at risk of having an affected child so that they
can be offered advice. Genetic screening and counseling
prior to conception is important for the control of
genetically determined disabilities. Many studies have
shown that genetic counseling of carriers, premarital
couples, couples with a disabled child and other family
members produces better understanding of the issues
involved and hence has an impact on the subsequent reproductive
decision. Several studies have shown that the number
of children born with a serious genetic disorder leading
to disability decreases significantly following genetic
counseling. The best example of the successful application
of this prevention strategy to prevent the birth of
homozygotes for a certain disorder is the thalassaemia
control program in Cyprus. Through health education,
together with population screening and genetic counseling
of carriers and prevention of carrier marriages, it
was possible to reduce the homozygous affected births
from 53 per 8594 births in 1974 to 0 per 10 752 in 1988
and 2 per 10 830 in 1990. The percentage of prevention
achieved was 1.8% in 1974, 100% in 1988 and 97% in 1990.
A similar approach when applied to other disorders could
be equally successful.
- Immunization Programs
Programs of general immunization during infancy have
led to a remarkable decrease in, or in a few cases
a complete absence of, several infectious diseases
that used to be a major cause of disability. These
include poliomyelitis, tuberculosis, meningitis and
encephalitis.
- Improved Prenatal, Perinatal
and Postnatal Health Care
This aspect of prevention concentrates on the management
of maternal risk, factors at the time of delivery
and support for the premature or compromised neonate.
- Regulations and legislation
Certain health regulations and legislation, such as
mandating immunization of infants, also play an important
role in primary prevention.
- Other related Means
- Secondary Prevention
Secondary prevention strategies aim at reducing the duration
or severity of disability. These activities provide early
identification of the disabling condition followed by
prompt treatment and intervention to minimize the development
of disability. These strategies can be applied either
at the prenatal or neonatal level.
Neonatal screening (organized examination of all neonates
in order to diagnose specific disorders so that they can
be treated) is a well established preventive approach
and includes both clinical and biochemical screening.
In some countries, such information is available but in
others, there is no information on detection frequency
at birth of genetic disorders.
At the neonatal level, screening of neonates and proper
intervention in those affected have been successful in
reducing disability. The best known example of secondary
intervention is that of neonatal screening for phenylketonuria
(PKU), other aminoacidurias, hypothyroidism, the thalassaemias
and other haemoglobinopathies. In PKU and other aminoacidurias,
once the baby is diagnosed as having an abnormality, proper
measures are taken by providing special diets.
Biochemical screening was first introduced for PKU in
1966 when it was shown that a low phenylalanine diet started
in the first week of life prevents severe mental retardation.
To screen for PKU, blood samples are usually taken by
heel prick between 5 and 10 days after birth, when the
body's metabolism has stabilized sufficiently for the
results to be reliable. Screening for PKU is now established
in several countries and screening for other abnormalities
is also carried out, particularly since the advent of
recombinent DNA technology. Hypothyroidism diagnosed during
the neonatal period is treated by hormone replacement
therapy, which encourages normal development and prevents
complications such as mental retardation. In sickle-cell
disease and thalassaemia patients, early detection enables
better development and growth.
New forms of secondary prevention, such as genetic or
surgical manipulation of an affected fetus to eradicate
the biochemical or anatomical abnormality are being tried,
some with a high degree of success. This is true for congenital
heart disease, cleft lip and cleft palate, congenital
dislocation of the hip and others.
- Tertiary Prevention
Tertiary prevention aims at limiting or reducing the effects
of a disorder or disability that is already present. It
involves long-term care and management of a chronic condition,
e.g. rehabilitation or correction of the disability by
surgical measures or by adopting strategies by which the
disabled person can lead a normal or near normal life.
The main aims of rehabilitation of the disabled are:
- to increase awareness of disabilities and the needs
of disabled people;
- to encourage their full integration in society;
and
- to improve prevention and stimulate a more sensitive
and understanding attitude.
These measures also include special education programs.
Only 50 years ago, the majority of disabled people were
left illiterate. However, during the past three or four
decades, considerable efforts have been made to develop
special education programs to educate blind-deaf-mute,
deaf-mute, blind and mentally retarded patients. Special
schools with specially trained teachers have provided
excellent education programs which have helped disabled
people achieve goals that, in many ways, are similar to
those of normal individuals.
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