Can dependencies be passed on genetically

Genetic tests: what is it?

Human genetic material is in the form of chromosomes that are spun from DNA threads. Individual sections of DNA (deoxyribonucleic acid) are called genes. The human genome consists of more than 20,000 genes. Inheritance as well as influences from the environment or lifestyle and much more can lead to changes (mutations) in one or more genes or chromosomes. Not every mutation is directly connected with consequences for the carrier of the “faulty” genetic information. Mutations do not automatically lead to noticeable changes, restrictions or the outbreak of a disease. However, a gene mutation can be passed on to the offspring.

A distinction is made between the following three types of diseases that can be caused by a genetic mutation:

Chromosomal diseases

Such diseases are based on a change in the number or structure of chromosomes. When the number of chromosomes changes, individual chromosomes are present either singly or in triplicate instead of duplicating them. A well-known example of this is trisomy 21 ("Down syndrome", formerly "Mongolism"), in which the 21st chromosome is present three times. Changes in the chromosome structure come about through chromosomal reorganization, which means that individual chromosome pieces are lost (deletion), duplicated (duplication), exchanged (translocation), incorrectly present (inversion) or newly inserted (insertion).

Monogenic diseases

These diseases are caused by changes (mutations) in a single gene. Monogenic diseases are inherited and follow special inheritance patterns. Many monogenic changes have serious consequences, such as Huntington's disease or cystic fibrosis (cystic fibrosis).

Complex genetic diseases

A genetic component also plays a role in diseases such as arteriosclerosis, heart disease, diabetes, Alzheimer's disease and many cancers. Several altered genes play a role here, but environmental conditions and lifestyle also have a significant influence on the outbreak of complex genetic diseases.

When are genetic tests done?

Genetic tests (DNA analyzes) are not part of the standard examinations that are carried out on patients. These are mostly very specific questions for which they are used, especially if a hereditary connection exists or is suspected.

Diagnostic genetic tests

Diagnostic genetic tests are used to examine or determine the cause of existing diseases or to confirm clinical diagnoses.

Prognostic (predictive) Genetic testing

These tests are used to determine a predisposition to a certain genetic disease that may break out in the future or to determine a carrier status for such a disease. They are used when there are hereditary diseases in the family or relatives and family members who are not sick want to know whether they are predisposed to get sick in the future. Couples who want to have children can use such tests to obtain more detailed information on whether or how likely they would pass certain diseases on to their children if they have inherited diseases. The genetic diagnosis of viable cells before they are introduced into a woman's body as part of in vitro fertilization (pre-implantation diagnosis) is only permitted in Austria in exceptional cases in the case of very serious diseases (Reproductive Medicine Act).

Pharmacogenetic tests

These are genetic tests that allow statements to be made about the effects and metabolism of drugs. If necessary, based on these statements, an individual adaptation of the drug therapy for certain diseases can be made for patients.

Genetic analyzes on humans for scientific and medical purposes are regulated by the Austrian Genetic Engineering Act (GTG). In addition to the approval of facilities that carry out predictive genetic tests, this law also regulates education, consent, advice, documentation and data protection in connection with genetic analyzes.

Genetic tests provide in-depth information on:

  • Hereditary diseases, including certain
  • prenatal issues (special prenatal diagnostics),
  • Malformations in children,
  • Developmental disorders in children,
  • unfulfilled desire to have children,
  • multiple miscarriages,
  • Clarification of parentage (paternity test),
  • (medical) research questions,
  • Criminology e.g. for identification.

Genetic counseling

Genetic tests are not carried out without the knowledge and consent of the person concerned. As a rule, genetic counseling is offered in advance, during which information is provided in detail and in an understandable manner about the procedure, the significance as well as its advantages and disadvantages and possible consequences.

Genetic counseling will usually be offered to you before genetic tests are performed. This is also required by law for most genetic tests (Genetic Engineering Act). Genetic counseling supports patients in this process, it offers help before, during and after genetic tests, for example in the form of psychological support. During genetic counseling, the enlightening specialist will provide you with precise and objective information about the procedure as well as the advantages and disadvantages in a detailed and understandable manner.

He / she will explain the possible risks and discuss with you the consequences of a genetic test. All of this is worked out on the basis of your specific situation, so that you can decide freely and well-informed whether you want to have a genetic test carried out. This also only happens after you have given your written consent. Even after consenting and performing a genetic analysis, patients may at any time notify that they do not want to know the results or the consequences thereof. This “right not to know” is also laid down in the Genetic Engineering Act.

What happens with a genetic test?

Very little sample material is required for genetic testing. Depending on the test, method and purpose of the examination, this can be, for example, small amounts of blood, saliva, hair, nails, skin, a swab of the oral mucosa, sperm and much more. In special prenatal tests, small pieces of the mother cake (chorionic villi) or the amniotic fluid of the pregnant woman are examined. Various modern methods are available for examining the test material. Science and research are very active in this area and new or improved techniques are constantly being developed.

Family history provides particularly informative information. The doctor will work out and discuss with you your family tree (usually over three generations) as well as all health-related data: which diseases exist or have occurred in the family, what causes of death there were and much more.

What are the risks of a genetic test?

Even if the techniques are state-of-the-art, the informative value of genetic tests is limited. A disease does not necessarily have to break out even if the test result is positive, and there is no guarantee that it will not break out even if the result is negative.

One and the same mutation can trigger different clinical pictures or individually different manifestations of the same disease. In most cases, a genetic test cannot therefore provide any information about the severity of the disease that will break out in the future, and the person concerned may remain completely symptom-free. Usually only the most common genetic changes are examined in a genetic test. This means that other, rarer mutations can be "overlooked". Furthermore, it is also possible that mutations in different genes can lead to the same clinical picture.

The awareness of a possible illness that is "slumbering" in one can sometimes become a heavy burden and trigger many emotions such as insecurity, stress, fear, feelings of guilt, etc. Psycho-social support can be helpful here, for example from a clinical psychologist, psychotherapist.

Beware of tests from the Internet

Commercial genetic tests from the Internet are not advisable in principle. Such tests are usually not used to examine classic (monogenic) hereditary diseases, but rather gene variants that are intended to make statements about an increased or decreased risk of common diseases such as diabetes, heart disease or obesity. In most cases, the examined gene variants are scientifically and clinically unsecured and are of little significance. Compulsory, detailed and individual genetic advice before and after performing a genetic analysis is not usually given in the case of genetic tests from the Internet.

Safe handling of your data

Genetic data is highly sensitive information. Of course, the person tested does not want their genetic data to fall into the “wrong hands”. There are fears of the "transparent man". In order to counteract this, there are strict legal framework conditions in Austria with the Genetic Engineering Act. In addition to your own decision for or against a test, the law also regulates the handling of data from tests. The data may only be passed on with your express written consent for a specific purpose. Employers and insurance companies are prohibited from querying genetic data in Austria. The transfer of data from genetic analyzes for the examination of acquired, i.e. non-hereditary mutations to insurance companies - but not to employers - is exempt from the ban.

In addition, genetic data may only be used by the “European Charter of Fundamental Rights” for the detection, prevention or therapy of a disease, for legal proceedings or criminal investigations. The legal basis is the Genetic Engineering Act, Federal Law Gazette 510/1994, Section IV - Genetic Analysis and Gene Therapy in Humans, as amended.

Whom can I ask?

If you are interested in genetic counseling or in certain genetic tests, it is best to contact the following offices:

  • Specialist in medical genetics,
  • Specialist in human genetics,
  • Institutions or institutes for medical genetics, e.g. at (university) clinics, more under Genetic Tests: Advice & Help.

All facilities approved for performing predictive genetic analyzes in accordance with Section 68 GTG are listed in the gene analysis register of the Federal Ministry for Health and Women.

If you have a predisposition to a particular hereditary disease that would have severe physical, mental, and social effects if it broke out, it may be helpful to seek additional non-medical care. Clinical psychologists, psychotherapists, social workers and other counseling institutions or self-help groups are particularly available to provide advice.

How are the costs going to be covered?

The costs of genetic counseling are covered by the social security agencies. A medical referral is required for this. The costs of many genetic tests are covered by the social security agencies. Certain genetic tests have to be paid for by the patient himself / herself. The costs incurred vary depending on the provider, practice or institute.

Overview: Genetic Tests Next ArticleNext Article "Paternity Tests"

The literature used can be found in the bibliography.

last updated March 30, 2017
Approved by the health portal editors
Last expert examination by Prim. Univ. Doz. med. Hans-Christoph Duba
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