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Genetic Testing

Legislation of genetic testing in Europe and USA is not consistent, this leads to huge diffenences for for the availability of medical genetic testing or direct-to-consumer genetic testing. In Germany, the Gendiagnostik-Gesetz (GenDG, Gene Diagnostic Act) and the Guidelines of the commision of genetic testing (GEKO) have comprehensively revised the conditions for genetic testing (Grimm et al., 2011). Before genetic testing, the patients has to recieve comprehensive explanation of the advantages and risks of the planned test. Written informed consent has to be obtained before the test. The GenDG distinguishes the following investigations:

Diagnostic genetic testing:

Differential diagnosis for a present condition of disease.

Predictive genetic testing:

Use of a genetic test in an asymptomatic person to predict the future risk of a disease.

Prenatal genetic testing:

Use of a genetic test to detect changes in a fetus's genes or chromosomes before birth.

Genetic counseling:

After a diagnostic genetic test and before and after a predictive or prenatal genetic test, a genetic counseling of the patient with a particularly qualified doctor should be done (a must in Germany due to GenDG). The genetic counseling includes the clarification of the question, anamnesis with family tree, explanation of the (possible) findings with consideration of the individual disease probability and consequences of the disease. Important counseling principles are a comprehensible presentation of the genetic principles, decision alternatives should be presented open-ended and the right not to know should be observed.

Genetic tests

Genetic tests are indicated to identify genetic changes in specific genes. Current used molecular genetic examination techniques are not suitable as a search test, the tests aim at specific genes. Various laboratory techniques are used such as the polymerase chain reaction (PCR), southern blot (detection of known mutations) and gene sequencing (Search for new mutations in defined genes). Modern techniques such as Multiplex ligation-dependent probe amplification (MLPA) and Next-Generation Sequencing (NGS) are becoming more accurate and efficiant, allowing the entire genome to be sequenced and searched at once.

References

  Deutsche Version: Genetische Untersuchung