Home > Encyclopedia of Nursing & Allied Health > Genetic Counseling

Definition

Genetic counseling is a communication process by which personal genetic risk information is translated into practical information for families. Genetic counselors are health care professionals with specialized training and experience in the areas of medical genetics and counseling. Genetic counselors are able to assist individuals and families by:

• Helping people to understand information about birth defects or genetic disorders. This includes explaining patterns of inheritance, recurrence risks, natural history of diseases, and genetic testing options.
• Providing nondirective supportive counseling regarding emotional issues related to a diagnosis or testing options.
• Helping individuals and families make decisions with which they are comfortable, based on their personal ethical and religious standards.
• Connecting individuals and families with appropriate resources, such as support groups or specific types of medical clinics, locally and nationally.

Purpose

There are several purposes or aspects to be addressed within the scope of genetic counseling. These include obtaining a pedigree; tracing ethnicity; exploring issues of consanguinity; and documenting exposures to toxins, diseases, or environmental agents during pregnancy.

Pedigree

In all types of genetic counseling, an important aspect of the counseling process is information gathering about family and medical history. Information gathering is performed by drawing a chart called a pedigree. A pedigree is made of symbols and lines that represent a family history. To accurately assess the risk of inherited diseases, information about three generations of the family, including health status and cause of death, is usually needed. If a family history is complicated, information from more distant relatives may be helpful, and medical records may be requested for any family members who have had a genetic disorder. Thorough examination of a family history may enable a counselor to calculate the probability of occurrence of genetic disorders in the future.

Ethnicity

In obtaining a family history, a genetic counselor asks about a person's ethnicity or ancestral origin. There are some ethnic groups that have a higher chance of being carriers of some genetic diseases or abnormalities. For instance, the chance that an African American is a carrier of a gene for sickle cell disease is one in 10. People of Jewish or central European ancestry are likely to be carriers of several conditions, including Tay-Sachs disease, Canavan's disease and cystic fibrosis. People of Mediterranean ancestry are likely to be carriers of a type of anemia called thalassemia. Genetic counselors discuss inheritance patterns of these diseases, carrier risks, and genetic screening or testing options.

Consanguinity

Another question a genetic counselor asks in obtaining a family history is whether the couple are related to one another by blood. The practice of marrying or having children with relatives is infrequent in the United States, but is more common in some countries. When two people are related by blood, there is an increased chance for their children to be affected with conditions that are inherited in a recessive pattern. In recessive inheritance, each parent of a child affected with a disease carries a single gene for a disease. The child gets two copies, one from each parent, and is affected. People who have a common ancestor are more likely than unrelated people to be carriers of genes for the same recessively inherited disorders. Depending on family history and ethnic background, blood tests can be offered to couples to get more information about the chance of these conditions occurring.

Exposures during pregnancy

During prenatal genetic counseling, the counselor will ask about pregnancy history. If a woman has taken medications or has had exposure to a potentially harmful substance from the environment such as a chemical, toxin, or radiation, the genetic counselor can discuss the possibility of adverse effects. Ultrasound is often a useful tool to look for some effects of exposure.

Precautions

There are no physical precautions that are needed before genetic counseling. However, persons who will receive the results of genetic tests should be prepared mentally and emotionally for the possibility of unpleasant information. This includes discussing if they want to know the results of genetic testing and what choices they may have to make based on the information supplied.

Description

Types of genetic counseling

Genetic counselors work with people concerned about the risk of an inherited disease or condition. These people represent several different populations. Prenatal genetic counseling is provided to couples that have an increased risk of birth defects or inherited conditions, and are expecting a child or planning a pregnancy. Pediatric genetic counseling is provided to families with children suspected of having a genetic disorder or with children previously diagnosed with a genetic disorder. Adult genetic counseling is provided to adults with clinical features of an inherited disease or a family history of an inherited disease. Cancer genetic counseling is provided to those with a strong family history of certain types of cancer. Ethics are an important component of genetic counseling.

Prenatal genetic counseling

There are several different reasons a person or couple may seek prenatal genetic counseling. If a woman is age 35 or older and pregnant, there is an increased chance that her fetus may have a change in the number of chromosomes present. Changes in chromosome number may lead to mental retardation and birth defects. Down syndrome is the most common change in chromosome number that occurs proportionally more often in the fetuses of older women. Couples may seek prenatal genetic counseling because of abnormal results of screening tests performed during pregnancy. A blood test called the alpha fetal protein (AFP) test is offered to all pregnant women. This blood test screens for Down syndrome, open spine defects (spina bifida), and another type of mental retardation caused by a change in chromosome number called trisomy 18. When this test is abnormal, further tests are offered to get more information about the chance of these conditions actually occurring in the fetus. Another reason that people seek prenatal genetic counseling is a family history of birth defects or inherited diseases. In some cases, blood tests of the parents may be available to indicate if their children would be at risk of being affected. Genetic counselors assess risk in each case, help persons to understand their risks, and explore how they feel about or will cope with these risks.

Prenatal tests that are offered during genetic counseling include level II ultrasounds, maternal serum AFP screening, chorionic villus sampling (CVS), and amniocentesis. Level II ultrasound is a detailed ultra-sound surveying fetal anatomy for birth defects. Ultrasound is limited to detection of structural changes in anatomy and cannot detect changes in chromosome number. The maternal serum AFP screening is used to indicate if a pregnant woman has a higher or lower chance of having a child with certain birth defects. This test can only provide information concerning the probability of a birth defect. The screening cannot diagnose an actual birth defect. CVS is a way of learning how many chromosomes are present in a fetus. A small piece of placental tissue is obtained for these studies during the tenth to twelfth weeks of pregnancy. Amniocentesis is also a way of learning how many chromosomes are present in a fetus. Amniotic fluid is obtained for these studies, usually between 15 and 20 weeks of pregnancy. There is a small risk of miscarriage associated with both of these tests. Genetic counseling regarding these procedures involves the careful explanation of benefits and limitations of each testing option. A genetic counselor also tries to explore how persons feel about prenatal testing and the impact of such testing on the pregnancy. Genetic counselors are supportive of any decision a person makes about whether or not to have prenatal tests performed.

Pediatric genetic counseling

Families or pediatricians seek genetic counseling when a child has features of an inherited condition. Any child who is born with more than one birth defect; mental retardation; or dysmorphic features has an increased chance of having a genetic syndrome. A common type of mental retardation in males for which genetic testing is available is Fragile X syndrome. Genetic testing is also available for many other childhood illnesses such as hemophilia and muscular dystrophy. Genetic counselors work with medical geneticists to determine if a genetic syndrome is present. This process includes a careful examination of family history, medical history of the child, review of pertinent medical records in the family, a physical examination of the child, and sometimes blood work or other diagnostic tests. If a diagnosis is made, then a medical geneticist and genetic counselor review what is known about the inheritance of the condition, the natural history of the condition, treatment options, further examinations that may be needed for health problems common in the diagnosed syndrome, and resources for helping the family. The genetic counselor also helps the family adjust to the diagnosis by providing emotional support and counseling. Many families are devastated by receiving a diagnosis, learning of the likely outcome for the child and by the loss of the hoped for healthy child. There would also be a discussion about recurrence risks in the family and who else in the family may be at risk.

Adult genetic counseling

Adults may seek genetic counseling when a person in the family decides to be tested for the presence of a known genetic condition; when an adult begins exhibiting symptoms of an inherited condition; or when there is a new diagnosis of someone with an adult-onset disorder in the family. In addition, the birth of a child with obvious features of a genetic disease leads to diagnosis of a parent who is more mildly affected. Genetic counseling for adults may lead to the consideration of presymptomatic genetic testing. Testing a person to determine the likelihood for a condition existing before any symptoms occur is an area of controversy. Huntington's disease is an example of a genetic disease for which presymptomatic testing is available. This is a neurological disease resulting in dementia. Onset of the condition is between 30 and 50 years of age. Huntington's disease is inherited in an autosomal dominant pattern. If a person has a parent with the disease, the risk of being affected is 50%. Would presymptomatic testing relieve or create anxiety ? Would a person benefit from removal of doubt about being affected? Would knowing about the condition help a person with life planning? Genetic counselors help people sort through their feelings about such testing and whether or not the results would be helpful to them.

Cancer genetic counseling

A family history of early onset breast, ovarian, or colon cancer in multiple generations of a family is a common reason a person would seek a genetic counselor who works with people who have cancer. While most cancer is not inherited, there are some families in which a dominant gene is present and causing the disease. A genetic counselor is able to discuss the chances that the cancer in the family is related to a dominantly inherited gene. The counselor can also discuss the option of testing for the breast and ovarian cancer genes, BRCA1 and BRCA2. In some cases the persons seeking testing have already had cancer but others have not. Therefore, presymptomatic testing is also an issue in cancer genetics. Emotional support is important for these people, as they have often lost close relatives from cancer and are fearful of their own risks. For families in which a dominant form of cancer is detected through genetic testing, a plan can be made for increased surveillance of disease symptoms.

Ethical issues in genetic counseling

Prenatal diagnosis of anomalies or chromosomal abnormalities may lead to a decision about whether or not a couple wishes to continue a pregnancy. Some couples choose to continue a pregnancy. Prenatal diagnosis gives them additional time to emotionally prepare for the birth of the child and to gather resources. Others choose not to continue a pregnancy in which problems have been diagnosed. These couples have unique emotional needs. Often the child is a very much desired addition to the family and parents are devastated that the child is not healthy. Presymptomatic testing for adult-onset disorders and cancer raises difficult issues regarding the need to know and the reality of dealing with abnormal results before symptoms occur. The National Society of Genetic Counselors has created a Code of Ethics to guide genetic counselors in caring for people. The Code of Ethics consists of four ethical principles:

• Beneficience is the promotion of personal well-being in others. The genetic counselor is an advocate for the person being counseled.
• Non-maleficience is the concept of doing no harm to a person.
• Autonomy is recognizing the value of an individual, the person's abilities and point of view. Important aspects of autonomy are truthfulness with persons, respecting confidentiality, and practicing informed consent.
• Justice is providing equal care for all, freedom of choice, and providing a high quality of care.

The main ethical principle of genetic counseling is the attempt to provide nondirective counseling. This principle again points to an individual-centered approach to care by focusing on the thoughts and feelings of each person. Five percent of the Human Genome Project budget is designated for research involving the best way to deal with ethical issues that arise as new genetic tests become available. Genetic counselors can help people navigate through the unfamiliar territory of genetic testing.

Preparation

Persons should be apprised of possible outcomes and given the opportunity to discuss their feelings prior to undergoing genetic tests. There is a burden associated with knowing the probability of a future outcome. Difficult decisions may be required as a result of learning genetic information through testing. The process of adequately preparing an individual for genetic counseling is called informed consent. Ethical genetic counselors always obtain informed consent prior to undertaking any genetic tests.

Aftercare

Persons must be provided access to competent counselors and therapists. Such professionals can assist in processing the feelings and reactions that may emerge as a result of receiving the findings of genetic tests.

Complications

The complications that arise from the process of genetic counseling are most commonly mental and emotional. Individuals and couples who have received genetic counseling often experience mental changes such as depression and anguish when they receive unfavorable results about tests. Complications include the need to make difficult decisions regarding themselves, their families, or their unborn children. This is also referred to as a burden of knowing, meaning that likely but unwanted outcomes may become known before they occur. Depending on the condition, personal preferences and situation, persons may elect to continue with a pregnancy that is likely to result in a child with one or more abnormalities, terminate a pregnancy, select a different partner, or decide not to have children. These are all difficult situations that may require the assistance and intervention of a trained mental health counselor or therapist.

Results

The results given to a person during genetic counseling are highly individualized and depend on the nature of tests being performed and the issues of importance to the person being counseled.

The results of the process of genetic counseling vary. Genetic counseling offers information to people, thereby allowing them to make informed choices. Some of the options may not be easy or pleasant to contemplate. However, they are based on hard data rather than on wishes, hopes, or some other non-scientific basis. Genetic counselors have an ethical duty to obtain informed consent from individuals prior to beginning genetic counseling, provide unbiased information and the ability to interact in a non-judgmental or coercive manner.

Health care team roles

Genetic counselors are specially trained members of a health care team who have a master's degree in genetic counseling. They receive referrals from obstetricians, pediatricians, family physicians, and other doctors. They interpret the results of tests from laboratory personnel, medical geneticists, and pathologists. They refer people to therapists and counselors for assistance in resolving issues that arise from the process of genetic counseling.

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KEY TERMS

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Canavan disease—A serious genetic disease more common among the Eastern European Jewish population that causes mental retardation and early death. Canavan disease is caused by the lack of an enzyme called aspartoacylase.

Cystic fibrosis—A respiratory disease characterized by chronic lung disease, pancreatic insufficiency, and an average age of survival of 29 years. Cystic fibrosis is caused by mutations in a gene on chromosome seven that encode a transmembrane receptor.

Dysmorphic feature—A subtle change in appearance such as low set ears or a flattened nasal bridge that suggests a genetic syndrome may be present.

Fragile X syndrome—The most common inherited cause of mental retardation in males. People with Fragile X syndrome often have large ears, a long face, hyperextensible finger joints, hyperactivity or autism. Fragile X syndrome is caused by an expansion in a gene on the X chromosome. Some females are also affected. Human Genome Project—An international collaborative project among scientists to map the genetic sequence of all the chromosomes. This project is funded by the National Institute of Health in the United States.

Informed consent—Provision of complete information to a competent individual regarding a treatment or test. Part of informed consent is to ensure a person's understanding of the advantages and disadvantages of a procedure and to obtain voluntary authorization to perform the procedure. Sickle-cell anemia—A chronic, inherited blood disorder characterized by crescent-shaped red blood cells. It occurs primarily in people of African descent, and produces symptoms including episodic pain in the joints, fever, leg ulcers, and jaundice.

Tay-Sachs disease—A genetic disease affecting young children of eastern European Jewish descent. This disease is caused by the lack of an enzyme called hexosaminidase A. This deficiency results in mental retardation, convulsions, blindness and, finally, death.

Thalassemia—An inherited group of anemias occurring primarily among people of Mediterranean descent. It is caused by abnormal formation of part of the hemoglobin molecule.

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L. Fleming Fallon, Jr., MD, DrPH