If you and your partner are newly pregnant, you may be amazed at the
number and variety of prenatal tests available to you. Blood tests, urine tests,
monthly medical exams, diet questionnaires, and family history forms crowd
your schedule and your desk, but each of these helps to assess the health of
you and your baby - and to predict any potential health risks.
Unlike your parents, you may also have the option of genetic testing. These tests
identify the likelihood of passing certain genetic diseases or disorders (those caused
by a defect in the genes, the tiny, DNA-containing units of heredity that determine
the characteristics and functioning of the entire body) to your children. Some of the
and Tay-Sachs disease (a fatal disease affecting the central nervous system). If
your history suggests that genetic testing would be helpful, you may be referred
to a genetic counselor. Or you might decide to seek out genetic counseling yourself.
What do genetic counselors do, and how can they help your family-to-be?
What Is Genetic Counseling?
Genetic counseling is the process of evaluating family history and medical records,
ordering genetic tests, evaluating the results of this investigation, and helping
parents understand and reach decisions about what to do next.
Genetic tests are done by analyzing small samples of blood or body tissues. They
determine whether you, your partner, or your baby carry genes for certain inherited
Genes are made up of DNA molecules, which are the simplest building blocks of heredity.
They are grouped together in specific patterns within a person's chromosomes, forming
the unique "blueprint" for every physical and biological characteristic of that person.
Humans have 46 chromosomes, arranged in pairs in every living cell of our bodies. When
the egg and sperm join at conception, half of each chromosomal pair is inherited from
each parent. This newly formed combination of chromosomes then copies itself again and
again during fetal growth and development, passing identical genetic information to each
new cell in the growing fetus. Current science suggests that human chromosomes carry
about 30,000 genes. An error in just one gene (and in some instances, even the alteration
of a single piece of DNA) can sometimes be the cause for a serious medical condition.
Some diseases, such as Huntington's disease (a degenerative nerve disease) and Marfan
syndrome (a connective tissue disorder), can be inherited from just one parent. Most
disorders cannot occur unless both the mother and father pass along the gene. Some of
these are cystic fibrosis, sickle cell anemia, and Tay-Sachs disease. Other diseases, such
as Down syndrome, are not inherited. In general, they result from an error (mutation) in
the cell division process during conception or fetal development. Still others, such as
achondroplasia (the most common form of dwarfism), may either be inherited or the result
of a genetic mutation.
Genetic tests don't yield easy-to-understand results. They can reveal the presence,
absence, or malformation of genes or chromosomes. Deciphering what these complex
tests mean is where a genetic counselor comes in.
Who Are Genetic Counselors?
Genetic counselors are professionals who have completed a master's program in medical
genetics and counseling skills. They then pass a certification exam administered by the
American Board of Genetic Counseling. This profession has existed officially only since
1971, when the first class of master's degree genetic counselors graduated from Sarah
Lawrence College. (Interestingly, your counselor will probably be a "she." According to
a January 2000 survey by the National Society of Genetic Counselors, 94% of genetic
counselors are female.)
Genetic counselors can help identify and interpret the risks of an inherited disorder, explain
inheritance patterns, suggest testing, and lay out possible scenarios. (They refer you to
a doctor or a laboratory for the actual tests.) They will explain the meaning of the medical
science involved. They also provide support and address any emotional issues often raised
by the results of the genetic testing.
Who Should See One?
Most couples planning a pregnancy or who are expecting do not need genetic
counseling. About 3% of babies are born with birth defects each year, according
to the U.S. Centers for Disease Control and Prevention - and of the malformations
that do occur, the most common are also among the most treatable. Cleft palate
and clubfoot, two of the more common birth defects, can be surgically repaired,
as can many heart malformations.
The best time to seek genetic counseling is before becoming pregnant, when a
counselor can help assess your risk factors. But even after you become pregnant,
a meeting with a genetic counselor can still be helpful. Robert Resta, a genetic
counselor, cites the example of babies born diagnosed with spina bifida
birth. Recent research suggests that delivering a baby with spina bifida via cesarean
section (avoiding the trauma of travel through the birth canal) can minimize damage
to the baby's spine - and perhaps reduce the likelihood that the child will need a
You should consider genetic counseling if any of the following risk factors apply to you:
If a standard prenatal screening test (such as the alpha fetoprotein test) yields an
If an amniocentesis yields an unexpected result (such as a
chromosomal defect in the unborn baby).
If either parent already has children with birth defects or
- If the mother-to-be has had two or more miscarriages or
babies that died in infancy.
If the mother-to-be will be 35 or older when the baby is born.
(Chances of having a child with Down syndrome increase with
the mother's age: a 35-year-old woman has a one in 350
chance of conceiving a child with Down syndrome. This chance
increases to one in 110 by age 40 and one in 30 by age 45.)
- If parents are concerned about genetic defects that occur
frequently in their ethnic or racial group. (African-American
couples are most at risk for having a child with sickle cell anemia;
Jewish couples of central or eastern European descent may
be carriers of Tay-Sachs disease; couples of Italian, Greek, or
Middle Eastern descent may carry the gene for thalassemia,
a red blood cell disorder.)
What to Expect During a Visit With a Genetic Counselor
Before you meet with a genetic counselor in person, you will be asked to gather
information about your family history. The counselor will want to know of any
relatives with genetic disorders, multiple miscarriages, and early or unexplained
deaths. The counselor will also want to look over your medical records, including
any ultrasounds, prenatal test results, past pregnancies, and medications or you
may have taken before or during pregnancy.
If more tests are necessary, the counselor will help you set up those appointments
and track the paperwork. When results come in, the counselor will call you with the
news. Often, counselor will encourage you to come in for a discussion.
The counselor will study your records before meeting with you so you can make
the best use of your time together. During your session, he or she will go over
any gaps or potential problem areas in your family or medical history. The counselor
can then help you understand the inheritance patterns of any potential disorders
and help assess your chances of having a child with those disorders.
He or she will distinguish between risks that every pregnancy faces and risks that
you personally face. Even if you discover you have a particular problem gene, science
cannot always predict the severity of the related disease. For instance, a child with
cystic fibrosis can have debilitating lung problems - or, less commonly, milder
You and your family will have to decide what to do next. Genetic counselors help you
adjust to the difficulties and uncertainties you face and understand your options.
If you've learned prior to conception that you and/or your partner is at high risk for
having a child with a severe or fatal defect, your options might include:
pre-implantation diagnosis, which occurs when eggs that
have been fertilized in vitro (in a laboratory, outside of
the womb) are tested for defects at the 8-cell (blastocyst)
stage - and only nonaffected blastocysts are implanted in
the uterus to establish a pregnancy
- using donor sperm or donor eggs
If you've received a prenatal diagnosis of a severe or fatal defect,
your options might include:
preparing yourself for the challenges you'll face when
you have your baby
fetal surgery to repair the defect before birth (Surgery
can only be used to treat some defects, such as spina
bifida or congenital diaphragmatic hernia, a hole in the
diaphragm that can cause severely underdeveloped lungs.
Most defects cannot be surgically repaired.)
For some families, knowing that they will have an infant with a severe or
fatal genetic condition seems too much to bear. Other families are able to
adapt to the news - and to the birth - remarkably well.
Genetic counselors can share the experiences they've had with other
families in your situation. But they will not suggest a particular course of
action. A good genetic counselor understands that what is right for one
family may not be right for another.
Genetic counselors can, however, refer you to specialists for further help.
For instance, many babies with Down syndrome are born with heart defects.
Your counselor might encourage you to meet with a cardiologist to discuss
heart surgery, and a neonatologist to discuss the care of a post-operative
newborn. Genetic counselors can also refer you to social workers, support
groups, or mental health professionals to help you adjust to and prepare
for your complex new reality.
Finding a Genetic Counselor
Working with a genetic counselor can be reassuring and informative, especially
if you or your partner have known risk factors. Talk to your doctor if you feel you
would benefit from genetic counseling. Many doctors have a list of local genetic
counselors with whom they work. You can also contact the National Society for
Genetic Counselors for more information.
Reviewed by: Linda Nicholson, MS, MC
Date reviewed: January 2002
Source: KidsHealth www.KidsHealth.com is a project of The Nemours Foundation which is dedicated to improving the health and spirit of children. Today, as part of its continuing mission, the Foundation supports the operation of a number of renowned children's health facilities throughout the nation, including the Alfred I. duPont Hospital for Children in Wilmington, Delaware, and the Nemours Children's Clinics throughout Florida. Visit The Nemours Foundation to find out more about them and its health facilities for children http://www.nemours.org/no/