QUESTION: Explain two types of genetic
screening that can be done and how they work?
ANSWER:
Genetic screening
- Genetic screening refers to a study of a person DNA to identify
genetic susceptibility to particular disease or abnormalities.
- Genetic screening refers to the medical test which recognize
changes of protien, chromosome or genes.
The common two types genetic screening are,
- Newborn Screening
- Prenatal testing
NEWBORN SCREENING
- Generally newborn screening begins with a blood test 24 hours
to 48 hours after a baby born.
- After that when the baby is 1 to 2 weeks old, a second blood
test is performed by the baby's pediatrician.
- Newborn testing is performed by pierce the baby heel to collect
a small drops of blood.There is no risk associated with procedure
but baby feel few discomfort.
- Then the collected blood placed on a specific paper and for
testing send it to the laboratory.
- After 2 to 3 weeks, the report is sent to the baby's doctors
clinic.
- If a baby is born in home or other birthing centre rather than
hospital, then the screening test is done by the nurse by
collecting the blood sample from the newborn baby.
- In addition to this test a pulse oximetry test also done by the
doctor to check the oxygen level in the blood of the new born
baby.
PRENATAL TESTING
- Prenatal testing is a type of screening test in which the test
can identify whether the baby is more or less likely to have the
birth defects or whether the baby have genetic disorder.
- Prenatal test includes ultrasound test, blood test,prenatal
cell free DNA screening.
- There are three types of screening test of prenatal testing.
These are First trimester screening test, second trimester
screening test,pre-natal cell free DNA screening
- First trimester screening test measure the size of the clear
space of the tissue at the back of baby's neck.In this testing
health care provider offered for ultrasound and blood test of the
baby.
- Second trimester screening identify the level of four substance
in baby's blood.Generally this test indicates the risk which is
caused by the chromasomal condition such as down syndrome.In this
test health care provider also offered for another blood test of
the baby known as Quad screen.
- Pre-Natal cell free DNA screening refers to the blood test in
which examine the fetal DNA in the maternal bloodstream to screen
for the increase chance of chromosome problem such as down
syndrome