Genetic Counseling: An Essential Component of Patient Care
Dr. med. Imma Rost, Dr. med. Margret Götz-Sothmann
Genetics is the science that deals with the analysis of the structure and function of genes and the laws of inheritance. Recent findings and the development of new testing methods have made genetics a central area in the field of medicine. The fact that nearly all diseases have a genetic basis, a genetic disposition, and the possibility to detect smallest changes in the human genome, have brought genetic diagnostics to a new dimension. To the same extent the significance of genetic counseling is increasing in the area of preventive medicine. The focus of genetic counseling is the discussion of an individual problem caused by a genetic predisposition. The counselor provides information on the diagnosis, the course of the disease as well as possible treatment, the inheritance of the disease and the recurrence risk as well as on pre- and postnatal cytogenetic and molecular genetic diagnostic possibilities. Information on the precise diagnosis, family history, a three-generation pedigree as well as pre-existing conditions are indispensable. In the case of rare or unclear dysmorphic syndromes, an extensive physical examination and documentation is carried out to clasify the disorder by comparison with syndrome databases. Goal of genetic counseling, which is always voluntary, is to enable the patient to make his or her own independent decision regarding life and family planning as well as personal disease prevention.
Genetic diseases are of major importance in every area of medicine; therefore, it is crucial for a physician to have genetic knowledge in order to conduct successful preventive counseling or family counseling. About 3% of all children are born with a genetic disease, malformations or disabilities. The percentage increases to 7-8% if diseases with a later onset are included. Whenever there are indications for a genetic risk, the affected person has to be informed about the possibility of genetic counseling. Genetic counseling is part of patient care and the costs are covered by the health insurance.
Genetic counseling is a non-directive communication process (GenDG §10 section 3). It is to help individuals, a couple or a family to understand medical genetic facts, consider options and thus make informed, independent, and future-oriented decisions, especially regarding genetic testing.
The Genetic Diagnosis Act (Gendiagnostikgesetz, GenDG), in force since February 1, 2010, regulates the conditions under which genetic diagnostic procedures are to be carried out. The genetic diagnostic commission (Gendiagnostik-Kommission, GEKO), which is located at the Robert Koch Institute, is providing guidelines to specify the regulations and to help implementing them in practice. GenDG requires genetic counseling in the case of any prenatal and predictive genetic diagnostic procedure prior to testing and once the results are at hand. Any genetic diagnostic procedure requires both the offer of genetic counseling and written informed consent of the patient. According to the GenDG the clarification given by the responsible doctor ("responsible medical person" GenDG) before obtaining informed consent is of particular importance. Thereby the responsible medical doctor does not have to provide genetic counseling but has to recommend or arrange it if necessary. Medical specialists from other areas may conduct genetic counseling if they acquire additional qualifications in the area of genetic counseling (Zusatzqualifikation zur fachgebundenen genetischen Beratung) (see guidelines GEKO). The recipient of laboratory results is always the responsible doctor; in contrast to genetic counseling, in which the written summary is primarily going to the counselee.
According to the the law concerning the amendment of the Pregnancy Conflict Law, in force since January 1, 2010, the responsible doctor is required to offer the pregnant patient in-depth psychosocial counseling and to provide contact to a support group or disability associations if prenatal diagnostics show pathological findings. According to § 218b section 1 StGB there has to be a 3-day period between communicating the diagnosis and the indication of termination of pregnancy. Written confirmation from the pregnant woman indicating that she has been offered counseling or that she chooses to forego counseling must be obtained.
In the end of 2011 the law of regulation of the preimplantation genetic diagnosis (PräimpG) came into effect as the new paragraph 3a of the Embryo Protection Act; the decree was approved by the Bundesrat (Federal Council) on February 1, 2013, and is to be implemented within the following 12 months, therefore allowing pre-implantation diagnostics (PID) in Germany in the case of certain indications. These indications are elevated risk for miscarriage or stillbirth or predisposition of one or both parents to a severe hereditary disease. GenDG does not apply to PID; according to PräimpG, however, in-depth counseling regarding the medical, psychological and social consequences of the procedures associated with PID is to be conducted. The counselor must not be the doctor who carries out these procedures.
The major focus of genetic counseling is:
1. Genetic family counseling
2. Individual genetic counseling
In genetic family counseling, the emphasis lies on the health of future children. The most common questions include:
- Presence of diseases or malformations in the partner or close relatives
- Birth of a child with a disease, malformation or developmental delay
- Pregnancy affected by viral infection, medication, radiation, drug abuse
- Advanced maternal age
- Several miscarriages or stillbirths
- Fertility problems, unfulfilled desire for children
- Partners are blood relatives
In individual genetic counseling, the focus lies on a disease of the patient itself or the risk of developing a disease. Knowing the diagnosis is crucial for successful therapy. The most common problems include:
- Chromosome aberrations
- Diseases that are caused by mutation of a gene (see molecular genetics, monogenic disorders) and which exhibit various patterns of inheritance (autosomal dominant, recessive, sex-linked)
- Multifactorial diseases caused by the interaction of genes and environmental factors, such as atherosclerosis, hypertension, osteoporosis, thrombophilia, diabetes, tumor disorders, and congenital malformations.
Any genetic diagnostic procedure requires informed consent. Therefore, genetic counseling assisting the patient in making independent, individual decisions should always be carried out.
Dealing with pathological findings in prenatal or predictive diagnostic procedures is still problematic. The possibility of termination of pregnancy or the knowledge of a threatening disease, which may manifest years or decades in the future, always challenges ethical boundaries. How should one handle the knowledge, the right not to know? These questions form a large part of genetic counseling. Solutions vary according to one’s private situation, world view, religious and ethical beliefs; they are targeted exclusively at the interests of the affected patients and their families. Thus, genetic counseling is always individual.
Indications for prenatal diagnostics:
- abnormal ultrasound with a suspected chromosomal abnormality
- advanced maternal age (risk of chromosomal abnormalities rises from 1% at the age of 35 to 10% at the age of 46)
- previous child with a chromosomal abnormality
- balanced chromosome aberration in one parent (frequency 1:500; risk of unbalanced aberrations in children)
- monogenic disorders which can be diagnosed through molecular genetics
- severe, multifactorially caused malformations (recurrence risk approx. 5%)
Indications for chromosome analysis:
- physical and/or cognitive developmental delay
- malformations and/or signs of dysmorphia
- preceding miscarriages without gynaecological cause
Indications for postnatal array CGH:
- isolated developmental delay (IQ < 70 in children older than three) and normal chromosome analysis
- multiple signs of dysmorphia with normal chromosome analysis
- multiple malformations
- malformations or severe brain defects
In the course of prenatal diagnostics, array CGH may be indicated to clarify new chromosomal structural aberrations or in the case of abnormal ultrasound and normal chromosome analysis. Currently, array CGH is not covered by the statutory health insurance. The patient should be clearly informed about the possibilities, limitations and qualities of prenatal array CGH prior to the procedure, especially about the possibility that results might occur of which the clinical relevance currently cannot be clarified.
Indications for molecular genetic diagnostics
- Confirmation of a clinically suspected diagnosis; clarification of carrier status in monogenic diseases
- Clarification of the pathogenesis of a disease prior to preventive or therapeutic measures.
In the case of clinically and genetically heterogeneous diseases, high throughput methods (next generation sequencing, NGS) are already used to analyze several genes simultaneously. Thereby, information may be revealed that was not asked for. How to deal with this additional information has to be discussed with the counselee prior to testing and will therefore be a major part of genetic counseling in the future (see also statement of the german society of human genetics (GfH), May 22, 2013, www.gfhev.de).
Furthermore, next generation sequencing enables the non-invasive detection of chromosomal aberrations (non-invasive prenatal diagnostics/testing: NIPD/T) from small amounts of cell-free fetal DNA (cffDNA), which is detectable in the maternal blood during pregnancy. In this way, it will also be possible in the future to test for monogenic diseases of which the parents are carriers. This can be carried out at an early stage without the risk of intervention like in the case of chorionic villus sampling or amniocentesis. The NIPT tests currently in use only detect trisomy 21 or the most common aneuploidies. The result is a risk assessment; therefore, invasive diagnostic procedures are currently recommended if results are pathological. Sensitivity and specificity of all currently available tests are better than in first trimester screening; therefore, NIPT might in the future replace at least biochemical diagnostics in first trimester screening. The tests currently in use have been validated using risk groups; thus, the data is so far not automatically valid for pregnant women with low risk of chromosomal aneuploidies (e.g. young women, normal first trimester screening). Since the procedure is part of predictive diagnostics which will be evaluated statistically and will lead to risk assessment, it is crucial to provide counseling and to discuss the significance of the results in detail.
You can find a nearly complete list of centers providing genetic counseling in Germany, Austria and Switzerland on the homepage of the German Society of Human Genetics (GfH) www.gfhev.de. If you need further information or help with the selection of the right institution, please call our free hotline 0800-GENETIK (0800-4363845).