Genetic Counseling

But it's even more likely that you might seek and benefit from genetic counseling. This is a broader category that encompasses not only testing but also some old-fashioned medical detective work and professional counseling.

What is genetic counseling?

Genetic counseling is a health service that helps people identify and understand what particular traits they might pass on to their children. It is performed by doctors and nurses, as well as by specially educated health professionals who are certified as genetic counselors and come from a variety of disciplines, including biology, genetics, psychology, public health, and social work.

Genetic counselors are trained to be sensitive to the background and values of the people they advise. A responsible counselor will never push you toward or dissuade you from a particular course of action but will only supply the information you need to make your own decisions.

Why might I want to consult a genetic counselor?

Genetic counseling can help you make important decisions, such as whether to have more children and whether to seek preventive or early treatment for a disease or disorder for which you or your child is at high risk. Situations in which people commonly seek genetic counseling include planning a pregnancy after age 34; having suffered two or more miscarriages; being aware of a family history of an inherited disorder; or already having a child with an inherited disorder or birth defect.

"People usually go for genetic counseling because a child or another family member has an inherited disorder, which usually falls into one of two categories," says Christopher Cunniff, MD, FAAP, chair of the Section of Medical and Molecular Genetics and an associate professor of pediatrics at the University of Arizona, in Tucson. "It may be a structural problem, such as cleft lip or palate, or it may be a functional problem, such as mental retardation or a developmental disability."

Some people also seek genetic counseling to address concerns about serious disorders that affect their particular race or ethnic group. Such disorders include sickle-cell anemia, a blood disorder that affects mainly Blacks; thalassemia, another blood disorder, which afflicts mostly people of Mediterranean (usually Greek or Italian) ancestry; and Tay-Sachs disease, a degeneration of the brain that strikes primarily Jews of Central or Eastern European descent.

When is the best time to get genetic counseling?

If you are concerned about passing on an inherited disorder, it's best to seek genetic counseling before becoming pregnant. If you become aware of an inherited disorder in your family while you are pregnant, however, genetic counseling is still a good idea. It can help you understand the likelihood that your child will be affected and help you prepare emotionally and medically.

If you are interested in genetic counseling because you suspect your child has an inherited disorder, bring the matter to your pediatrician's attention so that she can refer you to a testing and counseling facility when appropriate. "Children can be evaluated at any age," says Dr. Cunniff, "but the earlier it's done, the better it is for supervising their health care. Potential problems can be treated or at least anticipated as soon as possible."

What is genetic testing?

Genetic testing is one tool used in the genetic counseling process. There are several types of genetic tests. The more sophisticated blood tests analyze DNA to determine a person's risk of developing, or passing on to his children, specific inherited disorders.

What disorders can genetic tests predict?

In addition to the ethnicity-specific conditions already mentioned, serious disorders that can be detected (or risk predicted) include cystic fibrosis, a disorder that causes overactivity of the exocrine glands, which produce mucus; and Huntington's disease, a degenerative disorder that affects the brain and nervous system.

Scientists have already identified the gene that causes idiopathic ventricular fibrillation, a condition that can cause a younger person's heart to stop beating for no apparent reason and that leads to an estimated 15,000 to 36,000 deaths each year. They are also close to isolating the gene responsible for autism, a brain disorder that originates in infancy and is characterized by repetitive behavior, language dysfunction, and the inability to interact socially.

Through sophisticated research, genes responsible for specific conditions are being located all the time, and genetic tests are being developed to identify them. The Human Genome Project is an ongoing effort by scientists throughout the world to map the estimated 80,000 genes in human DNA.

Does genetic counseling always involve genetic tests?

No. Genetic tests are an important tool in genetic counseling, but they are not always needed to predict the risk of developing or passing on a disorder. A genetic counselor can often glean a great deal of information based on your family health history, your personal health history, and any signs and symptoms of the disorder that you or your child might exhibit. In some cases, standard, nongenetic medical tests can also reveal the presence of inherited disorders.

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Genetics Refresher Course

Understanding what determines your child's risk of an inherited disorder means taking a quick trip back to biology class. Here are the simple basics of genetics:

DNA (deoxyribonucleic acid) is a large molecule that holds the instructions for making all the proteins a cell needs.

A gene is a piece of DNA that contains the instructions for making a specific protein. The human body has approximately 80,000 genes. Each plays a different part in determining a person's heath tendencies and physical makeup-everything from his eye color to his risk of heart disease. A child gets half of his genes from each of his parents.

Genes are contained in chromosomes, structures in the nucleus of the body's cells. Human cells have 46 chromosomes, arranged in pairs.

Genetic inheritance patterns are classified as dominant or recessive. If a parent passes on the gene for a dominant disorder (such as Marfan's syndrome, a connective-tissue disease), her child has a 50 percent chance of inheriting it. If both parents carry a gene for a recessive disorder (such as cystic fibrosis), their child has a 25 percent chance of inheriting it. If only one parent has the gene for a recessive trait, it will be overridden by the other parent's normal gene and will not cause the child to be affected.

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Creating a family health history

To help a genetic counselor accurately assess the risk of a particular disorder, it's important to furnish your child's complete family health history. In fact, even if you never seek genetic counseling, it's wise to have this record. It can be just as valuable to your child's pediatrician as to your own physicians in helping them make decisions about your care. Gather information on your parents (your child's grandparents), siblings, aunts, uncles, and cousins. Make sure you canvass both sides of your child's family-yours and your spouse's; the risk of some diseases vary according to which side of the family the disease has appeared in.

Here are three starting points for assembling a family health history:

Interview family members.
Providing a form for them to fill out may help jog their memory and will make your record-keeping easier.

Gather hospital and other medical records.
These should include copies of any exam results, hospital discharge summaries, and genetic tests performed on family members living and dead.

Request copies of death certificates.
These records, available from state health departments, note the person's age and cause of death.