PreImplantation Genetic Testing
Preimplantation Genetic Testing (PGT): Empowering Precision in Assisted Reproductive Technologies
Preimplantation Genetic Testing (PGT) is a remarkable advancement in assisted reproductive technologies that offers invaluable insights into the genetic health of embryos before they are transferred during in vitro fertilization (IVF) procedures. PGT encompasses different techniques that enable the identification of genetic abnormalities, chromosomal disorders, and specific genetic traits. With PGT, intended parents can make informed decisions to increase the chances of a healthy pregnancy and give birth to a genetically healthy child. Let's explore the various types of PGT, their benefits, risks, and who may benefit from these techniques.
1 PGT-A
PGT-A (Aneuploidy Screening):
PGT-A (Aneuploidy Screening) PGT-A, formerly known as PGS (Preimplantation Genetic Screening), focuses on the screening of embryos for numerical chromosomal abnormalities, known as aneuploidies. These abnormalities, such as extra or missing chromosomes, are often associated with failed implantation, miscarriages, or certain genetic disorders.
Benefits
PGT-A helps identify chromosomally normal embryos, increasing the chances of successful implantation and reducing the risk of miscarriage.
PGT-A can identify embryos with significant chromosomal abnormalities, allowing the selection of embryos free from common aneuploidies such as Down syndrome, Turner syndrome, or other chromosomal disorders.
Risks
PGT-A may encounter mosaic results, where embryos exhibit a mixture of normal and abnormal cells. The clinical significance and implantation potential of mosaic embryos are still under debate, and further testing or consultation with a genetic counselor may be recommended.
2 PGT-M
PGT-M (Monogenic Disorders)
PGT-M (Monogenic Disorders) PGT-M, formerly known as PGD (Preimplantation Genetic Diagnosis), is used to screen embryos for specific monogenic disorders or single-gene disorders. These disorders are caused by mutations in a single gene and can be inherited from one or both parents.
Benefits
PGT-M enables the identification of embryos unaffected by specific monogenic disorders such as Sickle cell disease, reducing the risk of passing on these disorders to future generations.
PGT-M allows individuals or couples at risk of transmitting a genetic disorder to have the option of selecting embryos free from the specific disorder, thus expanding their reproductive choices.
Risks
PGT-M relies on the identification of known genetic mutations. However, it may not detect novel or rare mutations that are not specifically tested for, and there is a small risk of misdiagnosis or false-negative results.
Who May Benefits
3 PGT-SR
PGT-SR (Structural Rearrangements)
PGT-SR (Structural Rearrangements) PGT-SR is performed for individuals or couples with structural rearrangements in their chromosomes, such as translocations or inversions. These rearrangements can disrupt the normal chromosomal structure and may result in infertility, recurrent miscarriages, or the birth of children with chromosomal imbalances.
Benefits
PGT-SR helps identify embryos with balanced chromosomal arrangements, increasing the chances of successful implantation and reducing the risk of miscarriage.
PGT-SR can prevent the transfer of embryos with unbalanced chromosomal rearrangements, decreasing the likelihood of having children with chromosomal imbalances.
Risks
PGT-SR may not detect all structural rearrangements or may have limitations in detecting complex rearrangements. Further genetic counseling or testing may be recommended for individuals or couples with complex chromosomal rearrangements.