Gene testing is currently available for the HSP-spastin gene and
HSP-atlastin gene through Athena Diagnostics. These gene mutations cause
some 55% of the dominant forms of HSP.
Genetic testing is a highly personal choice. People are different,
and different people make different choices based on their individual
circumstances and personalities. It is sometimes hard for those who
choose to be tested to understand why someone would choose not to, and
vice versa.
Consider using the guidance of genetic counselors, mental health
professionals, clergy, or other professionals to help you determine if
testing is right for you.
Here are some pros and cons regarding testing.
The Case For Testing
1. If you test negative, it can be a tremendous load off your mind.
You will never have HSP, and you cannot pass the HSP gene on to your
children.
2. If you test positive, you have an opportunity to make informed
plans. These could be childbearing choices; informing children of a test
result; stimulating healthy habits regarding diet, exercise and stress
reduction; and making informed decisions regarding housing and health
and disability insurance. However, please remember: Some individuals do
not show symptoms until very late in life, or exhibit them very mildly.
Even when you test positive, there is no way to know when or how your
HSP will manifest itself.
3. You can get on with your life. While not happy to have HSP, people
can develop a greater sense of clarity about the meaning of their lives.
They may prioritize important things, let go of things that are trivial
and insignificant, and find ways to make a contribution to others.
People who test negative can have these same revelations.
4. You can develop a support system. It can be comforting to know
that you are not alone, that people care, and that other people have
found ways to deal with this. Your support system can include friends,
family, clergy, mental health counselors, a support group, or joining
on-line support resources.
The Case Against Testing
1. You can't change the results, and you can't go back to not-knowing
the results.
2. You can still keep guessing. You won't know when symptoms will
start, or how severe they will be. HSP is quite variable, and some
individuals do not show symptoms until very late in life.
3. Emotional trauma. Negative as well as positive results can be
traumatic. Individuals can be need a lot of help adjusting to a positive
result, and those who test negative can have difficult "survivor guilt".
4. The Risk of discrimination. If a positive report goes in your
medical record or insurance forms, you can risk being discriminated
against for life, health and disability insurance, jobs, etc. If an
insurance company can prove that you lied about your knowledge of your
test results, they can cancel your coverage.
5. Cost. The cost for the HSP-spastin gene is around $2,000. Some
insurance policies will cover it, and some will not.
In vitro fertilization and fetal cell testing
Although IVF and fetal cell testing is performed routinely for other
hereditary diseases, there are currently no known cases of these
procedures so far being done for individuals with HSP. However, there is
no reason that these procedures couldn't be utilized for HSP patients
whose families carry one of the discovered genes.
In Vitro Fertilization
Prenatal testing can be performed with in vitro fertilization, allowing
an unaffected embryo to be selected for implantation in the uterus.
Hormonal treatments are given to a woman so that multiple eggs ripen.
These eggs are removed and fertilized in vitro.
The fertilized eggs multiply for several days, going from one cell,
to two, to four, and then to eight cells. One cell is removed from the
8-cell embryo (this does not damage the embryo in any way), and genetic
testing is performed to look for HSP gene mutation or for genetic
markers linked with the disorder.
Unaffected embryos are implanted into the uterus and carried to term.
The baby will not have HSP, and will not carry the disease.
Fetal Cell Testing
Once a woman is pregnant, fetal cells can be evaluated for genetic
mutations by testing the chorionic villus, the tissue that make up the
placenta. To obtain cells, a doctor withdraws a small amount of tissue
from the placenta at 10 to 12 weeks of gestation by inserting a catheter
into the vagina or a needle through the abdomen. If it is determined
that the fetus carries an HSP gene, the parents may choose to terminate
the pregnancy.
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