Availability
Not every adult-onset genetic disorder is covered
by tests. Tests currently available cover only about
10% of known genetic diseases.
Tests but no therapies
At present, diagnostic information is often not matched
by effective treatment. Some people simply prefer
not to know that they might develop a disease if there
is currently no treatment available.
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Impact of the gene
Although genetic tests can identify a particular problem gene,
they cannot always predict how severely that gene will affect
the person who carries it.
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Interpretation of results
One of the most serious limitations of these tests
is the difficulty in interpreting a positive result,
because some people who carry a disease-associated mutation
never develop the disease. Scientists believe that these
mutations may work together with other unknown mutations
or with environmental factors to trigger the disease.
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Secondly, some tests give only a probability percentage that
you will develop the disorder (examples: Alzheimer's disease,
breast cancer, ovarian and colon cancer, and heart disease).
Many illnesses develop from a deadly mix of high-risk genes
and unhealthy lifestyle.
Physical and psychological effects
Since most genetic tests involve only a blood sample, there
is no significant physical risk.
Any risks have more to do with the way the results of the
test might change both the person's life and the lives of
his or her family.
Knowing that one carries a disease gene can cause
depression or anger. It may also affect decisions
to have children.
On the other hand, knowing that one does not (or will
not) have the disease may bring relief and comfort.
However, some people may feel guilty.
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