PGT
Preimplantation Genetic Testing
Preimplantation Genetic Testing is done in conjunction with an IVF cycle to ensure only genetically normal embryos will be selected for transfer into the uterus for implantation.
Benefits of Embryo Screening Technique
With PGT, one or two cells are taken from the embryo on Day 3 or 5 and assessed for chromosomal defects that may lead to miscarriages or genetic disorders. This embryo screening technique has many benefits, including:
- Boost the success rates of pregnancy and live birth with IVF treatment
- Reduce the rate of miscarriage
- Reduce the risk of the embryo inheriting a genetic disease
- Only normal embryos will be transferred to the mother’s womb
There are 2 types of genetic tests which are used to identify genetic flaws in embryos, which are Pre-Implantation Genetic Testing for Aneuploidy (PGT-A) and Pre-Implantation Genetic Testing for Monogenic Diseases (PGT-M).
Preimplantation Genetic Testing for Aneuploidy (PGT-A)
Preimplantation Genetic Testing for Aneuploidy was previously known as Pre-implantation Genetic Screening (PGS). PGT-A works to identify embryos with the correct number of chromosomes, which is 46 chromosomes. The benefit of doing this testing is to improve IVF implantation rates and reduce miscarriage rates. This testing is highly recommended for:
- Couples who are of advanced maternal age (above 37)
- Couples with a history of recurrent pregnancy loss
- Couples with repeated IVF failure
- Male partners with severe male factor infertility
PGT-A could test for diseases such as Down’s Syndrome (Trisomy 21), Patau Syndrome (Trisomy 13), Edward’s Syndrome (Trisomy 18), Turner Syndrome (XO), Klinefelter Syndrome (XXY), Triple X syndrome (XXX), Jacob’s Syndrome (XYY).
PGT-A is a routine procedure readily available at TMC Fertility for all patients.
Preimplantation Genetic Testing for Monogenic Diseases (PGT-M)
Preimplantation Genetic Testing for Monogenic Diseases was also previously known as Preimplantation Genetic Diagnosis (PGD). This testing is done to identify embryos with genes for specific diseases. By doing this testing, parents could reduce risks of passing on an inherited condition. We recommend this testing for couples who have a family history of genetic diseases and worry about passing it on their offspring, such as thalassaemia, Marfan syndrome, Huntington’s disease, cystic fibrosis, sickle cells disease, haemophilia.
PGT-M requires a personalised test, as it is a test tailor-made to look for specific genetic disorders running in a family, and requires a pre-work out. PGT-M can also be run in conjunction with HLA typing.
high resolution
Next Generation Sequencing
PGT using the latest High Resolution Next Generation Sequencing technology
The High Resolution-Next Generation Sequencing (Hr-NGS) is the most advanced preimplantation screening to date, with each sample given an additional molecular code to eliminate the possibility of errors. The DNA collected from the embryo is tested directly, without the use of lights or markers as with earlier PGT screenings.
The Hr-NGS tests all 24 chromosomes with a single cell from the embryo, and contains information that indicates not just the condition of the embryo but the potential health risks of the child decades down the line. Hr-NGS is expected to change the world of genetics in time to come, offering uncannily accurate predictions of a person’s health conditions even before birth, fully embodying its name as a screening of the ‘next generation’.