Chromosomal abnormality happens when a cell has too many or too few chromosomes. The most common form of chromosomal anomaly is Down’s syndrome. If a parent has a chromosomal anomaly, she/he will pass it on to the child. PGD or Preimplantation Genetic Testing aims to select only the embryos with normal chromosomal count and only these embryos are implanted to achieve a healthy pregnancy and bring down the number of children affected with a chromosomal anomaly.
The risk of Aneuploid pregnancy:
The older a woman is when she is trying to conceive (aged 35 or more), the higher the risk of Aneuploid pregnancy (carrying a baby with genetic or chromosomal abnormality). Most of these pregnancies end in miscarriages and a few that come to term produce babies with chromosomal abnormalities.
Causes of Chromosomal Abnormality:
Usually, chromosomal abnormalities occur due to an error in the cell division. Meiosis refers to the cell division, which the sperm and the egg undergo during the development procedure. Normally, meiosis breaks the chromosomal material into two equal halves, so that each of the parents contributes 23 chromosomes to the pregnancy. However, when the number of chromosomes in the cell goes up or down than the normal, it results in genetic/chromosomal anomalies.
PGD Procedure for a Chromosomal Anomaly:
If a couple elects to go for Preimplantation Genetic Diagnosis, they have to undergo ICSI Cycle. ICSI cycle initiates a fertilization cycle to produce embryos. When the embryos reach upto day 5 and blastocyst are formed, they are biopsied and further sent to genetic lab for detecting the chromosomal abnormalities. The embryos are incubated for the entire duration of the genetic screening. Only the embryos that the genetic test clears are implanted. PGD never reveals the gender of the embryo.
PGD can help detect the single genetic disorders that may lead to the following ailments:
- Cystic fibrosis
- Muscular dystrophy
- Sickle cell anaemia
- Turner syndrome
PGD is a revolutionary science that can help root out incurable disorders linked to genetics. It ensures that pregnancy is sustained until term and a healthy baby is born.