what is Genetic testing? and how is it helping family in pregnancy planning?
Genetic genetic testing
The genetic examination includes examining the genetic material (DNA), which is considered the database that carries instructions related to the functions of the body, as genetic tests can reveal changes (mutations) in the genes and these mutations will lead to defects in the body system and its functions later. Although these tests can provide important information that is used to diagnose, treat and prevent diseases, this does not necessarily mean that a positive result indicates a disease, and on the other hand, a negative result does not guarantee that no problem will be found. So why and how are these tests done?
What is a genetic gene test?
In fact, it is not a single test, but rather a set of tests that depend on examining the genetic material at any stage of life. The genetic material is fixed that we inherit from our parents and remain with us and accompany us throughout our life. So testing can be performed at any stage from the embryo stage (while performing the IVF technique), or in early childhood through adulthood. Of course, the reasons for doing this analysis differ according to the symptoms and the disease that the person complains of, and sometimes it is done to detect a problem, diagnose it or to determine the best way to treat it.
Why is genetic testing done?
Genetic testing plays an important role in determining the risk of developing some diseases in addition to determining the treatment sometimes, and the most important reasons for conducting these tests:
Diagnosis of the disease:
This is when the patient suffers from symptoms that may be caused by genetic changes, for example, a genetic test can be used to confirm the diagnosis of cystic fibrosis or Huntington's disease (it is a genetic progressive disease that causes damage to nerve cells in the brain and as a result, involuntary movements, emotional disturbances and a deterioration in the mental state appear. ).
Prenatal or fetal safety checks (NIPT):
If a woman is pregnant, the tests can reveal some types of genetic abnormalities in the fetus (Down syndrome and trisomy 18 syndrome are two genetic disorders that are often screened as part of prenatal genetic testing).
The test may be performed on a sample of the mother's blood, and confirmed by another test on a sample of amniotic fluid or a chorionic villus biopsy.
This is the most common type of genetic testing. This type of test is important because if the results show that there is a disorder such as congenital hypothyroidism or sickle cell disease, care and treatment can begin immediately.
This test is also called preimplantation genetic diagnosis (implantation), and it can be used when performing the tube baby technique, in which one cell is taken from the embryo at the beginning of its formation and examined to look for any genetic disorders, and this allows only healthy embryos to be returned to the uterus.
Predicting disease and getting tested before symptoms appear:
If the patient has a family history of a genetic condition, then a genetic test before any symptoms appear if the patient is at risk of developing this genetic condition, for example this type of test may be useful to determine the risk of certain types of colon and rectal cancer.
Testing for the person carrying the disease (the carrier of the disease):
If the patient has a family history of inherited disorders (such as sickle cell anemia or cystic fibrosis) it may be preferable to take the test before having children, this test can detect genes associated with a wide range of diseases and can determine whether the patient or his partner is a carrier of this. The disease and are able to pass it on to their children.
• Determining the appropriate drug for the genetic condition:
As this test helps to determine the type of treatment and its dose, and the best example here is breast cancer, so if a woman with breast cancer carries a special mutation related to this cancer, her daughters are at risk of infection, so more analyzes must be done for them, and the presence of this mutation interferes with determining the type The most appropriate treatment for her.
What are the risks of these tests?
Risks vary depending on how the test is performed. A cheek swab test or a blood sample is not associated with the occurrence of any problem, but prenatal tests such as amniocentesis or placenta sampling may be associated with bleeding or even a miscarriage.
What types of samples are to be tested?
The test aims to take a sample for analysis, and only the method of taking the sample differs, it may be easy for children and adults, as it is possible to take a swab from the cheek or draw blood from the arm, and for newborns, the blood sample is taken by pricking the child's heel.
In embryology, the matter is completely different, so the sample needs to be withdrawn for a small amount of amniotic fluid for genetic testing before birth, where the doctor inserts a needle through the abdominal wall and into the uterine cavity to collect a small amount of amniotic fluid for testing, and in some cases it may require taking Chorionic villus sampling (CVS) for prenatal genetic testing. A single cell may be taken from the embryo during the IVF technique before the embryos are returned to the womb.
Are the results accurate?
The accuracy of the results and methods of interpretation and reading vary greatly from one case to another, and it is related to the method of taking the sample and the type of disease that we are looking for, so the results must be read by an expert person, as some cases may need to be followed up in other, more accurate ways, for example, positive results of fetal safety checks need to be confirmed with procedures Others are more accurate such as amniotic villi biopsy. Therefore, one should not rush to read the results and judge them, but rather consult doctors with experience in this field to reach the best possible judgment.
• CDC: Genetic Testing
• MAYO CLINIC: Genetic testing
• MedlinePlus: What is genetic testing?
• NHS: Genetic and genomic testing
• WebMD: Genetic