What is genetic counseling?

The Establishment of Genetic Counseling

Historically, people have long understood that some physical characteristics are hereditary and that particular defects are often common among relatives. This concept was widely accepted by expectant parents and influenced the thinking of many scientists who experimented with heredity in plants and animals. Many efforts were made to understand, predict, and control the outcome of reproduction in humans and other organisms. Gregor Mendel’s experiments with garden peas in the mid-1800s led to the understanding of the relationship between traits in parents and their offspring. During the early twentieth century, Walter Sutton proposed that newly discovered hereditary factors were physically located on complex structures within the cells of living organisms. This led to the chromosome theory of inheritance, which explains mechanically how genetic information is transmitted from parents to offspring in a regular, orderly manner. In 1953, James Watson and Francis Crick (along with Maurice Wilkins and Rosalind Franklin) discovered the double-helix structure of DNA, the molecule that carries the genetic information in the cells of most living organisms. Three years later, human cells were found to contain forty-six chromosomes each.

These discoveries, along with other developments in genetics, periodically generated efforts (often misguided) to control the existence of “inferior” genes, a concept known as eugenics. Charles F. Dight, a physician influenced by the eugenics movement, left his estate in 1927 “To Promote Biological Race Betterment—betterment in Human Brain Structure and Mental Endowment and therefor[e] in Behavior.” In 1941 the Dight Institute for Human Genetics began to shift its emphasis from eugenics to genetic studies of individual families. In 1947, Sheldon Reed began working at the Dight Institute as a genetic consultant to individual families. Reed believed that his profession should put the clients’ needs before all other considerations and that it should be separated from the concept of eugenics. He rejected the older names for his work, such as “genetic hygiene,” and substituted “genetic counseling” to describe the type of social work contributing to the benefit of the family. As a result, the field of genetic counseling was born and separated itself from the direct concern of its effect upon the state or politics. In fact, Reed predicted that genetic counseling would have been rejected had it been presented as a form of eugenics.

Genetic counseling developed as a preventive tool and became more diagnostic in nature as it moved from academic centers to the major medical centers. In 1951, there were ten genetic counseling centers in the United States employing academically affiliated geneticists. Melissa Richter and Joan Marks were instrumental in the development of the first graduate program in genetic counseling at Sarah Lawrence College in New York in 1969. By the early 1970s, there were nearly nine hundred genetic counseling centers worldwide. By 2002 there were approximately two thousand genetic counselors in the United States not only working with individual families concerning genetic conditions but also involved in teaching, research, screening programs, public health, and the coordination of support groups. In 1990, the Human Genome Project
began as a fifteen-year effort coordinated by the U.S. Department of Energy and the National Institutes of Health to map and sequence the entire human genome, prepare a model of the mouse genome, expand medical technologies, and study the ethical, legal, and social implications of genetic research.

The Training of the Genetic Counselor

Most genetic counseling students have undergraduate degrees in genetics, nursing, psychology, biology, social work, or public health. Training programs for genetic counselors are typically two-year master’s-level programs and include field training in medical genetics and counseling in addition to a variety of courses focusing on genetics, psychosocial theory, and counseling techniques. During the two-year program, students obtain an in-depth background in human genetics and counseling through coursework and field training at genetic centers. Coursework incorporates information on specific aspects of diseases, including the prognoses, consequences, treatments, risks of occurrence, and prevention as they relate to individuals or families. Field training at genetic centers enables students to develop research, analytical, and communication skills necessary to meet the needs of individuals at risk for a genetic disease.

Many genetic counselors work with MD or PhD geneticists and may also be a part of a health care team that may include pediatricians, cardiologists, psychologists, endocrinologists, cytologists, nurses, and social workers. Other genetic counselors are in private practice or are engaged in research activities related to the field of medical genetics and genetic counseling. Genetic counseling most commonly takes place in medical centers, where specialists work together in clinical genetics units and have access to diagnostic facilities, including genetic laboratories and equipment for prenatal screening.

The Role of the Genetic Counselor

Prior to the 1960s, most genetic counselors were individuals with genetic training who consulted with patients or physicians about specific risks of occurrence of genetic diseases. It was not until 1959, when French geneticist Jérôme Lejeune discovered that children with Down syndrome
have an extra chromosome 21, that human genetics was finally brought to the attention of ordinary physicians. Rapid growth in knowledge of inheritance patterns, improvements in the ability to detect chromosomal abnormalities, and the advent of screening programs for certain diseases in high-risk populations all contributed to the increased interest in genetic counseling. Development of the technique of amniocentesis, which detects both chromosomal and biochemical defects in fetal cells, led to the increased specialization of genetic counseling. By the 1970s, training of genetic counselors focused on addressing patients’ psychosocial as well as medical needs. Genetic counseling thus became a voluntary social service intended exclusively for the benefit of the particular family involved.

Genetic counselors provide information and support to families who have members with genetic disorders, individuals who themselves are affected with a genetic condition, and families who may be at risk for a variety of inherited genetic conditions, including Huntington’s disease (Huntington’s chorea), cystic fibrosis, and Tay-Sachs disease. The counselor obtains the family medical history and medical records in order to interpret information about the inherited genetic abnormality. Genetic counselors analyze inheritance patterns, review risks of recurrence, and offer available options for the genetic condition. Other functions of genetic counselors include discussing genetic risks with blood-related couples considering marriage, contacting parents during the crisis following fetal or neonatal death, preparing a community for a genetic population screening
program, and informing couples about genetically related causes of their infertility. A pregnant patient is most commonly referred to a genetic counselor by an obstetrician because of her advanced age (thirty-five years or older).

In addition to obtaining accurate diagnosis of the genetic abnormality, genetic counselors strive to explain the genetic information as clearly as possible, making sure that the individual or family understands the information fully and accurately. The genetic counselor must evaluate the reliability of the diagnosis and the risk of occurrence of the genetic disease. Because the reliability of various tests will affect a patient’s decision about genetic testing and abortion, the counselor must give the patient a realistic understanding of the meaning and inherent ambiguity of test results. Most genetic counselors practice the principle of nondirectiveness and value patient autonomy. They present information on the benefits, limitations, and risks of diagnostic procedures without recommending a course of action, encouraging patients to reach their own decisions based on their personal beliefs and values. This attitude reflects the historical shift of genetic counseling away from eugenics toward a focus on the individual family. The code of ethics of the National Society of Genetic Counselors states that its members strive to “respect their clients’ beliefs, cultural traditions, inclinations, circumstances, and feelings as well as provide the means for their clients to make informed independent decisions, free of coercion, by providing or illuminating the necessary facts and clarifying the alternatives and anticipated consequences.”

Diagnosis of Genetic Abnormalities

In the latter half of the twentieth century, discoveries in genetics and developments in reproductive technology contributed to the advancements in prenatal diagnosis and genetic counseling. Prenatal diagnostic procedures eventually became an established part of obstetrical practice with the development of amniocentesis in the 1960s, followed by ultrasound, chorionic villus sampling (CVS), and fetal blood sampling. Amniocentesis, CVS, and fetal blood sampling are ways to obtain fetal cells for analysis and detection of various types of diseases. Amniocentesis, a cytogenetic analysis of the cells within the fluid surrounding the fetus, is performed between the fifteenth and twentieth weeks of gestation and detects possible chromosomal abnormalities such as Down syndrome and trisomy 18. The information obtained from CVS is similar to that obtained from amniocentesis, except the testing can be performed earlier in the pregnancy (during the tenth to twelfth weeks of gestation). Fetal blood sampling can be performed safely only after eighteen weeks of pregnancy. An ultrasound, offered to all pregnant women, uses high-frequency sound waves to create a visual image of the fetus and detects anatomical defects such as spina bifida, cleft lip, and certain heart malformations. Pedigree analysis may also be used for diagnostic purposes and to determine the risk of passing a genetic abnormality on to future generations. A pedigree of the family history is constructed, listing the sex, age, and state of health of the patient’s close relatives; from that, recurrent miscarriages, stillbirths, and infant deaths are explored.

Prenatal diagnostic techniques are used to identify many structural birth defects, chromosomal abnormalities, and more than five hundred specific disorders. Genetic counselors who believe that their client is at risk for passing on a particular disease may suggest several genetic tests, depending on the risk the patient may face. Screening of populations with high frequencies of certain hereditary conditions, such as Tay-Sachs disease among Ashkenazi Jews, is encouraged so that high-risk couples can be identified and their pregnancies monitored for affected fetuses. Pregnant women may also be advised to undergo testing if an abnormality has been found by the doctor, the mother will be thirty-five years of age or older at the time of delivery, the couple has a family history of a particular genetic abnormality, the mother has a history of stillbirths or miscarriages, or the mother is a carrier of metabolic disorders (for example, hemophilia) that
can be passed from mothers to their sons.

The Human Genome Project is expected to have a dramatic impact on presymptomatic diagnosis of individuals carrying specific diseases, multigene defects involved in common diseases such as heart disease and diabetes, and individual susceptibility to environmental factors that interact with genes to produce diseases. The isolation and sequencing of genes associated with genetic abnormalities such as cystic fibrosis, kidney disease, Alzheimer’s disease, and Huntington’s disease (Huntington’s chorea) allow for individuals to be tested for those specific conditions. Many genetic tests have been developed so that the detection of genetic conditions can be made earlier and with more precision.

Ethical Aspects of Genetic Counseling

With advancements in human genetics and reproductive technology, fundamental moral and ethical questions may arise during difficult decision-making processes involving genetic abnormalities for which families may be unprepared. Diagnosis of a particular genetic disease may allow individuals or families to make future plans and financial arrangements. However, improvements in the capability to diagnose numerous hereditary diseases often exceed the ability to treat such diseases. The awareness that an unborn child is genetically predisposed toward a disease with no known cure may lead to traumatic anxiety and depression. The psychological aspects of genetic counseling and genetic centers must therefore continue to be explored in genetic centers throughout the world.

Questions about who should have access to the data containing patients’ genetic makeup must also be considered as the ability to screen for genetic diseases increases, giving rise to a number of ethical issues. Violating patients’ privacy could have devastating consequences, such as genetic discrimination in job hiring and availability of health coverage. Employers and insurance companies have already denied individuals such opportunities based on information found through genetic testing. Disclosure of genetic information not only contributes to acts of discrimination but also may result in physical and psychological harm to individuals.

With data derived from the Human Genome Project increasing rapidly, problems arising from the application of new genetic knowledge in clinical practice must be addressed. The norm of nondirective counseling will be challenged, raising questions of who provides and who receives information and how it is given. Many believe that genetic counseling is beneficial to those faced with genetic abnormalities, while others fear that genetic counseling is a form of negative eugenics, an attempt to “improve” humanity as a whole by discouraging the birth of children with genetic defects. Since most genetic conditions can be neither treated nor modified in pregnancy, abortion is often the preventive measure used. Thus, ethical issues concerning the respect for autonomy of the unborn child must also be considered.

Key terms



genetic screening

:

the process of investigating a specific population of people to detect the presence of genetic defects




nondirective counseling

:

a practice that values patient autonomy and encourages patients to reach a decision that is right for them based upon their personal beliefs and values




pedigree analysis

:

analysis of a family’s history by listing characteristics such as age, sex, and state of health of family members, used to determine the characteristics of a genetic disease and the risk of passing it on to offspring




prenatal diagnosis

:

the process of detecting a variety of birth defects and inherited disorders before a baby is born by various imaging technologies, genetic tests, and biochemical assays





Bibliography

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