21st March is celebrated as Down’s syndrome day . Let us know a little about this .
What is Down’s Syndrome ?
A genetic syndrome characterized by mild to moderate intellectual disabilities , a particular kind of facial features- flattened face and nose , almond shaped slanting eyes , small ears and mouth , thyroid disease, heart disease , intestinal problems and sometimes Epilepsy , Leukemia and Alzheimer’s disease .
It occurs in about 1:500 births and risks increase with increasing maternal age .
There is an extra copy of chromosome 21 , hence the name Trisomy 21 .
What tests are done to detect Down’s syndrome ?
There are 2 kinds of tests- screening tests and diagnostic tests.
Screening tests tell us your risk of having a baby with Down’s syndrome ( along with Trisomy 13 and 18) whereas diagnostic tests either confirm or rule out the diagnosis .
Screening tests may be 1 st trimester or 2 nd trimester .
1 st trimester screening tests involve an ultrasound called the NT NB scan which is done at 11-14 weeks . It is clubbed with a blood test that tests for 2 proteins called B HCG and PAPP-A . These biochemical markers are taken at 10-14 weeks. An assessment of risk of Down’s syndrome is made taking these cumulative factors along with your age .
The second trimester screening involves assessment of 4 proteins in maternal blood ( quadruple test) along with a level 2 or anomaly ultrasound scan which specifically looks for some structural markers in the baby’s organs for Down’s syndrome .
The result will show as low risk or high risk . In case you are at high risk for the same , you may get the diagnostic tests done . Or there is also the option of a secondary screening test called NIPT . Consult your doctor for the best option for you .
Are there any risks to your baby with these screening tests ?
No .
What diagnostic tests are done to confirm or rule out the diagnosis ?
The diagnostic tests available are amniocentesis ( done at 16-20 weeks) that involves taking a bit of the amniotic fluid around the baby under ultrasound guidance and sending it for genetic testing for abnormal chromosomes .
The other test is CVS( Chorionic villous sampling that involves taking some placental tissue at 10-13 weeks and sending it for genetic testing .
Do diagnostic tests have risks?
In good hands the risks are low . There are however risks of miscarriage .1:200 with CVS and 1:300-1:600 with Amniocentesis.
What choices do you have ?
The choices are totally yours . You may decide to continue with a pregnancy even if proven to be a Down’s baby or you may decide to terminate pregnancy . The options of going in for screening tests and diagnostic tests ,should the screening tests be high risk are again yours to make . However do talk to your obstetritian regarding all the choices available .
This Down’s syndrome day let’s be a little more educated , a little more aware and empowered . This article is a small step in that direction .