Genetic Counseling-In General

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

more familiar genetic disorders are Down syndrome, cystic fibrosis, sickle cell anemia,

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

disorders.

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 before

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

wheelchair.

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

abnormal result.

If an amniocentesis yields an unexpected result (such as a

chromosomal defect in the unborn baby).

If either parent or a close relative has an inherited disease

or birth defect.

If either parent already has children with birth defects or

genetic disorders.

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

respiratory symptoms.

After Counseling

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

adoption

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.)

ending the pregnancy

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

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