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The scenario: You and your husband are 20-somethings
with graduate degrees and stable careers; it is the perfect time
to have a child. You both go in to see a genetic counselor before
trying to conceive. You learn about a variety of different genetic
diseases and decide it would be best for you both to undergo genetic
screening. The results show your husband is fine, but you are a
carrier of the Fragile X pre mutation. What does this mean? This
means you have a 50% chance of having a child with Fragile X Syndrome
(FXS), one of the leading causes of mental retardation, and there
is a 21% chance that you will have an early onset of menopause,
referred to as Premature Ovarian Failure (POF) (Sherman 2000b, Appendix
1). You could lose your ability to have children as soon as the
next year. Now, you must decide if you want to risk having a child
with an incurable disease, and you are under time restraints for
conception.
With such dramatic affects, early genetic screening
of the general female population is something to consider. Fragile
X Syndrome (FXS) is a genetically inherited disease causing mental
retardation that effects 1/4000 males and 1/8000 females (Crawford
et al., 1999). The cause is an increase in DNA nucleotides, CGG
repeats, in the Fragile X mental retardation gene 1 ( FMR1) found
on the X chromosome (Verkerk et al., 1999). The gene's location
is responsible for the higher susceptibility to men since men only
have one X chromosome, while women have two allowing for their healthier
copy to dominate. FXS is unique because the number of repeats can
expand in your children, which makes it more harmful to them than
you. However, while over 200 CGG repeats on both X chromosomes are
necessary to cause mental retardation in females, 60-200 repeats
in just one X chromosome can cause POF, an occurrence in 1/350 (Crawford
et al., 1999).
With earlier detection, women might opt to attempt
pregnancy earlier. Preliminary screening is simple. It involves
taking a little brush and lightly stroking the inside of your cheek.
With as little as that, you can plan your pregnancy with much more
information.
While having all the information possible sounds like
the best idea, anything concerning genetics always provokes ethical
issues. When should women be screened? If you were at risk for POF,
at what age would you want to know? Would you tell the man you intended
to marry, knowing that he wanted children? As a man, would you want
to know that the woman you intend to marry has a 50% chance of having
a mentally retarded child, and a 21% chance of not being able to
conceive after her late 20's? Will that be enough time to conceive
at least one child? Who will have access to your results? Is health
insurance going to be a problem with the knowledge of not only a
pre-existing condition but also a greater probability of having
children that are mentally retarded? The answers to these questions
are difficult, but not ones to be pushed aside. It is time to address
these questions and allow science to complement our changing lifestyles.
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