The genes show the future of health

Using genetic testing to predict the future?

05/20/2013

Healthy people sometimes become seriously ill. Others, who do not care about their health, live almost without complaint. An explanation for this can be found in part in our genetic material. So what's the point of genetic testing??

Angelina Jolie triggers new interest
In the case of actress Angelina Jolie, the breast cancer risk gene BRCA-1 was discovered through a genetic test. Molecular geneticists extracted the DNA from their cells and "read" the genome information stored there. Because of the increased risk of developing ovarian or breast cancer, Jolie had both breasts amputated and triggered a wave of worldwide interest in genetic diagnostics. Prophylactic mastectomies are considered questionable and only make sense in very few women, according to the American Cancer Society (ACS).

Only a dozen genital diseases treatable with gene therapy
The innate properties of each person on two times 23, so 46 chromosomes, which are located in the nuclei of the body cells, with him. Around 25,000 genes are located here and if there is a mistake in this blueprint, diseases can arise. Certain genetic defects can lead to specific conditions and can also be inherited. Scientists are trying to better read such errors in the genome and to interpret them correctly in order to enable healing with this knowledge. Jörg Epplen, Head of the Department of Human Genetics at the Ruhr University Bochum, does not yet see science so far. 7,000 diseases that are wholly or partially triggered by certain genes are known in research, but only about half of them manage to detect them by means of a genetic test. For example, in breast cancer or Huntington's disease.

But all this knowledge does not really help the research, "because even if we know the problem in the genes, we can not cure it by a long shot," says Epplen. Only a dozen genital diseases today are actually treatable with gene therapy, such as very rare immune system defects. To make matters worse, that a genetic test does not reveal all relationships, but in each case only a small section of the genes a cell.

Healthy lifestyle even with the best genetic conditions
It would be wrong to rely on his "good genes", because the lifestyle always plays a role, often even a more important than the inherited factor. So with a genetic test you can only get information about how likely the risk of the outbreak of a particular disease is, but only purely statistically. The physician says: "Even with the best genetic conditions, an unhealthy lifestyle could, for example, lead to a heart attack." The health-related future of a person can therefore not be automatically predicted by means of gene diagnostics.

Life-saving knowledge through genetic testing
Whether one should know at all, whether one is statistically more endangered, to get a certain illness, everyone must decide for themselves. Epplen says, "In fact, knowing about it sometimes makes sense." For example, it is known that the mutant gene that Angelina Jolie wears can cause breast and ovarian cancer in women and prostate cancer in men. If the affected person knows about the likelihood of a disease, they can opt for a close precautionary measure to immediately detect the onset of the illness and, as a result, treat it with life-saving treatment. However, Epplen also warns: "It should be clear, however, that such tests not only bring clarity. You can also put a lot of mental strain on you. "

Controversial preimplementation diagnostics
Another example is the genetic Huntington's disease, which is not curable and is passed on to about 50 percent of the children. Such inheritance would be avoidable with preimplantation genetic diagnosis (PID). For example, in the case of PID, an artificial insemination in the test tube is used to extract a cell with gene information of the possible fetus and, if the gene is present, the parents have the option of deciding against the baby. In Germany, PID is only permitted for the prevention of serious hereditary diseases as well as deaths or miscarriages. Only in specially certified centers may a PID be performed. It is banned in Switzerland and Austria. The German Ethics Council warned in a press release that sufferers often "incriminating information without intervention options" received.

Right to ignorance
However, some parents have their unborn child tested for genetic defects in the womb, including trisomy 21, the so-called Down syndrome. Previously, such tests were performed via invasive measures such as amniotic fluid or gynecological examinations. Meanwhile, from the blood of pregnant women from the tenth week of pregnancy is fairly predictable, whether the possibility of trisomy 21 exists. Epplen adds, "In so-called genetic counseling, we always point out the right not to know what our own genetic predispositions are" and many people have made use of this right.

Expensive and elaborate research will take decades to complete
For scientists, the challenge of the future lies in determining genetic relationships in common diseases such as Alzheimer's or colon cancer, blood sugar, high blood pressure, heart attacks or even Parkinson's disease. To meet this challenge, costly and expensive research is needed. The expert also said, "The difficult part is that we do not know which combination of gene mutations makes us ill - and which ones are completely harmless." He goes on to say, "It will take decades for us to fully understand genetic relationships here. "

A little optimism
One obstacle to fully understanding and correctly interpreting genes is that not all genes are inherited. Rather, some passages are so-called new mutations which occur for the first time in the examined person. The programs for predicting the disease significance of some genetic variations are currently even contradictory and therefore completely inadequate. Needed is therefore a great progress in the interpretation options. As a result, new procedures need to be developed and significant progress can only be expected in a few sub-areas over the next three to five years. Nevertheless, the scientist Epplen exudes a bit of optimism: "In ten years' time we will not yet know all the genetic combinations that are dangerous - but all those genes that are solely responsible for a particular disease." (Sb)

Read on:
Breast cancer: Gentest should prevent chemotherapy
Genetic test detects hereditary diseases in babies
Hereditary diseases cure with stem cells?
Blood test for Down syndrome Selection of humans?