GENETIC DISEASES IN IVF
Abnormalities in both males and females may cause implantation failure or miscarriage as well as birth defects in a resulting child. Preimplantation genetic testing evaluates embryos for genetic abnormalities prior to embryo transfer during IVF.
Genes is made up of DNA which is an essential part of heredity. Genes come in pairs, with one inherited from the male and one from the female parent. Genes are the dominant elements in DNA that determine a human’s development, function and personal attributes such as hair and eye color. A genetic disorder results when genes are not properly formed, either before birth or through mutation after birth.
Genetic disorders can cause infertility such as:
Individual infertility in the male or female
A single gene disorder inherited by an embryo can cause implantation failure or miscarriage.
A chromosomal abnormality in the embryo
Benefits of PGT
Higher chance of pregnancy
Reduced risk of miscarriage
More confidence in transferring a single embryo, avoiding health risks associated with twin or triplet pregnancies
Reduced number of IVF cycles needed to achieve pregnancy, potentially reducing the time to pregnancy and the costs of extra cycles
Types of Genetic Abnormalities
- PGT-A, or preimplantation genetic testing for aneuploidies was formerly known as PGS, preimplantation genetic screening. PGT-A is a reproductive technology used with an in vitro fertilisation (IVF) cycle. It is used to analyse the chromosomes of the embryos before their transfer into the womb. The purpose of PGT-A is to increase the chance of becoming pregnant and to lower the risk of miscarriage or risk of having a chromosomally abnormal child. The test is performed by extracting a single or few cells from the embryo produced through IVF. A PGT-A test reveals the number of chromosomes from each embryo.
The correct number of chromosomes (46) is necessary for the embryo to become a normal child.PGT-A enables the checking of all 23 sets of chromosomes including X and Y in each embryo so that only normal embryos are selected for transfer into the womb.
Example A : a pair of chromosome 21 is normal ; three chromosomes of 21 is Down’s Syndrome
- PGT – M enables couples with an inheritable genetic condition in their family to avoid passing it on to their children. It is a powerful test performed prior to implantation to help identify single gene defects within embryos created through IVF to avoid conceiving a child with a genetic disorder.
- PGT-SR is a test to identify embryos with the correct amount of genetic material (balanced/normal) and embryos that have extra or missing genetic material as a result of the translocation or rearrangement (unbalanced). PGT-SR reduces the chance of a failed implantation or miscarriage, or of having a child with chromosomal abnormality, and increase the likelihood of a healthy pregnancy after an IVF cycle.
- PGT HLA matching is used to identify embryos that are HLA compatible with a child who needs of bone marrow or cord blood transplant. PGT – HLA seeks to harvest and use stem cells in the umbilical cord blood (otherwise considered a waste material) of the newly born child.
