出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2018/06/06 14:09:51」(JST)
Genetic counseling is the process by which the patients or relatives at risk of an inherited disorder (or may be carrying a child at risk) are advised of the consequences and nature of the disorder, the probability of developing or transmitting it, and the options open to them in management and family planning. This complex process can be separated into diagnostic (the actual estimation of risk) and supportive aspects.[1]
The National Society of Genetic Counselors (NSGC) officially defines genetic counseling as the understanding and adaptation to the medical, psychological and familial implications of genetic contributions to disease.[2] This process integrates:
A genetic counselor is an expert with a Master of Science degree in genetic counseling. There are currently 37 accredited programs in the United States, four accredited programs in Canada, and six programs with the intent to become accredited [3]. In the United States they are certified by the American Board of Genetic Counseling.[1] In Canada, genetic counselors are certified by the Canadian Association of Genetic Counsellors. Most enter the field from a variety of disciplines, including biology/ biological sciences and social sciences such as psychology [4]. Genetic counselors should be expert educators, skilled in translating the complex language of genomic medicine into terms that are easy to understand. Genetic counseling helps one to know the chances of inheritance of a genetic disorder so that people can make informed decisions.
Genetic counselors work as members of a health care team and act as patient advocates as well as genetic resources to physicians. Genetic counselors provide information and support to families who have members with birth defects or genetic disorders, and to families who may be at risk for a variety of inherited conditions. They identify families at risk, investigate the problems present in the family, interpret information about the disorder, analyze inheritance patterns and risks of recurrence, and review available genetic testing options with the family.
Genetic counselors are present at high risk or specialty prenatal clinics that offer prenatal diagnosis, pediatric care centers, and adult genetic centers. Genetic counseling can occur before conception (i.e. when one or two of the parents are carriers of a certain trait) through to adulthood (for adult onset genetic conditions, such as Huntington's disease or hereditary cancer syndromes).
As of November 2017, 22 states require licensure to genetic counselors. These states are California, Connecticut, Delaware, Idaho, Illinois, Indiana, Kentucky, Massachusetts, Minnesota, Nebraska, New Hampshire, New Jersey, New Mexico, North Dakota, Ohio, Oklahoma, Pennsylvania, South Dakota, Tennessee, Utah, Virginia, and Washington. As of that time all other states besides Wyoming and Vermont were in progress of getting licensure and/ or in the rule making stage[5].
Graduates from an ABGC (American Board of Genetic Counseling) accredited program who have met specific criteria are eligible to take the examination which is offered twice per year by the ABGC. Although not every company requires its counselors to possess a certification, the certification shows that the practitioner has met the standards "necessary to provide competent genetic counseling services".[6]
Although genetic counseling has existed for over four decades, the first licenses for genetic counselors were not issued until 2002. Utah was the first state to do so. The American Society of Human Genetics (ASHG) has since encouraged more states to license genetic counselors before they are allowed to practice. The ASHG argues that requiring practitioners to go through the necessary training and testing to obtain a license will ensure quality genetic services as well as allow for reimbursement for counselors’ services. Laws requiring licensure ensure that "professionals who call themselves genetic counselors are able to properly explain complicated test results that could confuse patients and families making important health decisions".[7]
Insurance companies usually do not reimburse for unlicensed genetic counselors’ services. Patients who may benefit from genetic counseling may not be able to afford the service due to the expensive out-of-pocket cost. In addition, licensure allows genetic counselors to be searchable in most insurance companies’ databases which gives genetic counselors increased opportunities for earning revenue and clients the opportunity to see "the level of coverage insurers provide for their services".[7]
Any person may seek out genetic counseling for a condition they may have inherited from their biological parents.
A woman, if pregnant, may be referred for genetic counseling if a risk is discovered through prenatal testing (screening or diagnosis). Some clients are notified of having a higher individual risk for chromosomal abnormalities or birth defects. Testing enables women and couples to make a decision as to whether or not to continue with their pregnancy, and helps provide information that can be used to prepare for the birth of a child with medical issues.
A person may also undergo genetic counseling after the birth of a child with a genetic condition. In these instances, the genetic counselor explains the condition to the patient along with recurrence risks in future children. In all cases of a positive family history for a condition, the genetic counselor can evaluate risks, recurrence and explain the condition itself.
Individuals may seek out genetic counseling based on a known family history of disease, such as cancer. In the context of hereditary cancer, family history of breast, ovarian, pancreatic, colorectal, uterine, and prostate cancers are particularly relevant. Rare cancers, multiple cancers in a single individual, and particular cancer clusters (such as breast and ovarian, or uterine and colorectal) may be a good indication to seek out genetic counseling.
There is a growing need for genetic cancers in cardiology, neurology, and other burgeoning specialties such as psychiatry.
The goals of genetic counseling are to increase understanding of genetic diseases, discuss disease management options, and explain the risks and benefits of testing.[8] Counseling sessions focus on giving vital, unbiased information and non-directive assistance in the patient's decision-making process. Seymour Kessler, in 1979, first categorized sessions in five phases: an intake phase, an initial contact phase, the encounter phase, the summary phase, and a follow-up phase.[9] The intake and follow-up phases occur outside of the actual counseling session. The initial contact phase is when the counselor and families meet and build rapport. The encounter phase includes dialogue between the counselor and the client about the nature of screening and diagnostic tests. The summary phase provides all the options and decisions available for the next step. If patients wish to go ahead with testing, an appointment is organized and the genetic counselor acts as the person to communicate the results. Result delivery can happen both in person or via phone. Often counselors will call out results to avoid patients having to come back in as results can take weeks to be processed. If further counseling is needed in a more personal setting, or it is determined that additional family members should be tested, a secondary appointment can be made.
Families or individuals may choose to attend counseling or undergo prenatal testing for a number of reasons.[10]
Many disorders cannot occur unless both the mother and father pass on their genes, such as cystic fibrosis; this is known as autosomal recessive inheritance. Other autosomal dominant diseases can be inherited from one parent, such as Huntington disease and DiGeorge syndrome. Yet other genetic disorders are caused by an error or mutation occurring during the cell division process (e.g. aneuploidy) and are not hereditary. Testing can reveal conditions that, while debilitating without treatment, are mild or asymptomatic with early treatment (such as phenylketonuria). Genetic tests are available for a number of genetic conditions, including but not limited to:
Patients may be referred to a genetic counselor based on the diagnosis, or a strong family history of cancer. It is estimated that only 5-10% of cancers are hereditary, meaning that these cancers are due to a gene mutation that has been passed down in the family.[11] Some examples of known cancer syndromes are hereditary breast and ovarian cancer syndrome, hereditary non-polyposis colorectal cancer and Li-Fraumeni syndrome.[12] Meeting with a genetic counselor before undergoing genetic testing will help an individual to understand the test and what the results may mean for themselves and their family. Once the results are received, genetic counselors can help the patient to understand a positive or negative result. This counseling may involve providing emotional support, discussing recommendations for preventative care, screening recommendations or referrals to support groups or other resources.[13] For patients who have already been diagnosed with cancer, a positive test result may influence how the cancer is treated.[13]
Genetic Alliance states that counselors provide supportive counseling to families, serve as patient advocates and refer individuals and families to community or state support services. They serve as educators and resource people for other health care professionals and for the general public. Many engage in research activities related to the field of medical genetics and genetic counseling. The field of genetic counseling is rapidly expanding and many counselors are taking on "non-traditional roles" which includes working for genetic companies and laboratories.[citation needed] When communicating increased risk, counselors anticipate the likely distress and prepare patients for the results. Counselors help clients cope with and adapt to the emotional, psychological, medical, social, and economic consequences of the test results.
Each individual considers their family needs, social setting, cultural background, and religious beliefs when interpreting their risk.[14] Clients must evaluate their reasoning to continue with testing at all. Counselors are present to put all the possibilities in perspective and encourage clients to take time to think about their decision. When a risk is found, counselors frequently reassure parents that they were not responsible for the result. An informed choice without pressure or coercion is made when all relevant information has been given and understood.
If an initial noninvasive screening test reveals a risk to the baby, clients are encouraged to attend genetic counseling to learn about their options. Further prenatal investigation is beneficial and provides helpful details regarding the status of the fetus, contributing to the decision-making process. Decisions made by clients are affected by factors including timing, accuracy of information provided by tests, and risk and benefits of the tests. Counselors present a summary of all the options available. Clients may accept the risk and have no future testing, proceed to diagnostic testing, or take further screening tests to refine the risk. Invasive diagnostic tests possess a small risk of miscarriage (1-2%) but provide more definitive results. While families seek direction and suggestions from the counselors, they are reassured that no right or wrong answer exists. When discussing possible choices, counselor discourse predominates and is characterized by examples of what some people might do. Discussion enables people to place the information and circumstances into the context of their own lives.[15] Clients are given a decision-making framework they can use to situate themselves. Counselors focus on the importance of individual choice based on the experiences, morals, and viewpoints of the couple/individual/family. Testing is offered to provide a definitive answer regarding the presence of a certain genetic condition or chromosomal abnormality. There is often no therapy or treatment available for these conditions, and as such parents may choose to terminate the pregnancy.
After attending prenatal counseling, women have the option of accepting the risk revealed and having no further investigations during their pregnancy. They may choose to undergo noninvasive screening (e.g. ultrasound, triple screen, cell-free fetal DNA screening) or invasive diagnostic testing (amniocentesis or chorionic villus sampling).
After counseling for other hereditary conditions, the patient may be presented with the option of having genetic testing. In some circumstances no genetic testing is indicated, other times it may be useful to begin the testing process with an affected family member. The genetic counselor also reviews the advantages and disadvantages of genetic testing with the patient.
The plethora of information available can be overwhelming and counselors spend a large proportion of time clarifying details. Prenatal screening was first introduced nearly four decades ago, yet gaps still exist in public knowledge about the screening program. The general public is familiar with Down syndrome (trisomy 21), but is not aware of more uncommon conditions such as trisomy 18 (historically known as Edwards syndrome) and trisomy 13 (Patau syndrome). Clients are usually aware of diagnostic testing from friends, TV/press, or because of family history.
No simple correlation has been found between the change in technology to the changes in values and beliefs towards genetic testing.[16]
In China, genetic counseling is steered by the Chinese Board of Genetic Counseling (CBGC),[17] a not-for-profit organization. CBGC is composed of senior experts engaged in the genetics teaching and scientific researches. CBGC is committed to establishing standardized procedures of genetic counseling, training qualified genetic counselors, improving health for all, and reducing birth defects.
"Whether the process of genetic counseling is a form of psychotherapy is up for debate". The relationship between the client and counselor is similar as are the goals of the sessions. As a psychotherapist aims to help his client improve his wellbeing, a genetic counselor also helps his client to address a "situational health threat that similarly threatens client wellbeing". Due to the lack of studies which compare genetic counseling to the practice of psychotherapy, it is hard to say with certainty whether genetic counseling can be "conceptualized as a short-term, applied, specific type of psychotherapy". However, there few existing studies suggest that genetic counseling falls "significantly short of psychotherapeutic counseling" because genetic counseling sessions primarily consist of the distribution of information without much emphasis placed on explaining any long-term impacts to the client.[18]
Psychiatric genetic counseling is a controversial topic among many in the medical community. Some question its legitimacy due to the unknown cause of many psychiatric disorders. While many disorders have shown to have a genetic basis in twin studies, such knowledge means little for psychiatric genetic counseling if the exact genetic mechanism is still unknown. Those who support psychiatric genetic counseling argue that doctors can now do much more than offer risk estimates. Psychiatric genetic counselors can help "dispel mistaken notions about psychiatrist disorders, calm needless anxiety, and help those at risk to draw up a rational plan of action based on the best available information".[19]
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| 関連記事 | 「genetic」「counselling」「genet」 |