Down Syndrome
Q: What is Down Syndrome? How important is it for me to be screened
for it when I'm pregnant?
Dr. Donnica: Down Syndrome is a genetic disorder resulting from having
an extra chromosome, number 21 (3 copies instead of 2). It is the most frequent
cause of mild to moderate mental retardation in the United States. In addition,
babies born with Down syndrome may have numerous medical problems, including:
heart defects; speech, hearing, or vision problems; seizures; stomach or intestinal
disorders; trouble swallowing; thyroid problems; bone and joint problems; and
leukemia. Early learning intervention programs are highly recommended.
The only way to diagnose this disorder before birth is with an amniocentesis.
This procedure involves inserting a needle into the amniotic fluid under ultrasound
guidance, withdrawing a small amount of fluid, and then testing it. This is
usually recommended for mothers over the age of 35, when the risk of genetic
abnormalities greatly increases OR for those parents who have a family history
of any genetic abnormalities. Amniocentesis carries its own risks (notably the
risk of miscarriage or infection), so it is not a procedure for all women.
Another screening test is available -- a blood test for alpha-fetal protein,
or AFP. If this is abnormal, an ultrasound is recommended. Women should know
that an abnormal AFP should not be a cause for alarm as it has many false positive
results. Women should also know that an ultrasound exam alone is NOT a sufficient
screening test for Down syndrome (Journal of the American Medical Association,
2/28/01).
Created: 5/17/2001 - Donnica Moore, M.D.
