The occurrence of Down’s syndrome can be completely prevented by genetic testing. Genetic testing is the only way of determining the chances of having Down’s syndrome. Down’s syndrome is due to having an extra copy of 21st chromosome. Read on to find more about it.
The mode of functioning of an organism is determined by its genetic code. It is this genetic code that decides the structure of an organism and its behavior and adaptability in the environment that it is a part of. Being an organism, this is true in case of humans too. When there is a mistake or an undesired alteration in the human genetic code, there can be a series of physical and mental deficiencies.
Often these deficiencies do not get noticed and lay hidden or dormant in the system only to resurface at a later stage. The disease then gets manifested. Down’s syndrome is one such condition where the definitive symptoms of the disease don’t appear at the initial stage. The characteristics of the disease are only known at a much alter stage and the problems follow from there on. Genetic testing is the only procedure by which this disorder can be confirmed.
What is Down’s Syndrome?
Before discussing on genetic testing for the disease it is important to define in simple terms what is this disease all about. Down’s syndrome is a genetic condition which is also known as Trisomy 21. This means that the said person is having an extra copy of the 21st chromosome. This entails that the person is having 47 chromosomes instead of the usual 46.
There are certain characteristics and conditions that ensue due to this extra chromosome. The person may develop a flat facial structure and have a stunted growth. He or she is likely to have moderate to acute mental retardation. Although this is a rare case, as just one out of every 800 births can be found to be affected by this genetic condition. But the severity of the condition makes it imperative that the child be tested for his genetic configuration so that all possibilities of this disease are allayed.
Genetic Testing can Screen Down’s Syndrome – Test Procedures
This is the all important basic procedure for screening down’s syndrome. It is a series of steps which begins with a collection of blood sample. AFP
- This test is known as expanded AFP and is conducted between 15-20 weeks of the gestation period. The result is combined with the mother’s age on order to obtain the probability factor of the baby being born with down’s syndrome. This is actually a calculation of the risk factor of the baby developing this condition in later years. Aminiocentesis
– This genetic test is also conducted in the 15-20th week of gestation. A long needle is used to puncture the abdomen of the mother in order to draw out the amniotic fluid from the amniotic sac. A chromosomal analysis on this fluid sample is done under clinical conditions. The accuracy of this test is considered to be very high and it is important to note that it is not a misconception that this test carries a risk of miscarriage
. The risk is like one miscarriage in every 100 tests. According to researchers and pathologists, the risk factor is greatly dependant on the facility where the test is conducted. CVS
– In chorionic villus sampling (CVS), a tissue sample is collected from the placenta of the woman for conducting the genetic test through chromosomal analysis. Like amniocentesis the abdomen is punctured with the help of a catheter inserted through the cervix. Here too there is a risk of miscarriage but the positive aspect is that the test can be conducted at a very initial stage of pregnancy that is, on the 10-12th week.