Preimplantation Genetic Testing (PGT)
Selecting the best embryo from Preimplantation Genetic Testing (PGT) can reduce the time to pregnancy by giving a better choice of which embryo to use first.
PGT - Aneuploidies
Preimplantation Genetic Testing for Aneuploidies
The PGT-A test checks the number of chromosomes in each embryo at the blastocyst stage (a blastocyst is an embryo that has been developed in the laboratory for five or six days after fertilisation).
Due to the fact that many blastocysts have the wrong number of chromosomes (a condition known as aneuploidy), PGT-A is a powerful tool for selecting a good embryo for transfer. Aneuploidy can lead to miscarriages, birth defects and other complications.
What are the benefits of PGT-A
- if you have a normal/euploid embryo, then it has the same chance of implantation regardless of your age
- Lower miscarriage rate
- More certainty for people about the likely outcome of treatment
Who can benefit from PGT-A
- women of advanced age with good ovarian reserve,
- people who have had recurrent miscarriages,
- people not pregnant despite the transfer of several embryos (PGT-A may uncover a higher than expected chromosome abnormality rate),
- patients who are willing to go through more than one egg collection cycle to obtain a normal embryo
How does PGT-A works?
- About 5-6 cells are biopsied from each blastocyst using a fine glass needle
- The blastocysts are frozen for later use
- The cells are analysed at Sunfert’s state-of-the-art PGT laboratory
- Euploid blastocysts are selected and transferred at a later date after thawing
PGT-M can detect aneuploidy at low resolution.
PGT - Monogenic disorder
Preimplantation Genetic Testing for Monogenic disorders
For people who have a chance of passing on an inheritable genetic disorder to their child, such as Cystic Fibrosis, Huntington’s, Beta-thalassemia, Fragile X and Spinal Muscular Atrophy (SMA). These are caused by a change or mutation in the gene.
Who can benefit from PGT-M
- women who have had previous pregnancy termination(s) due to a serious genetic disorder
- couples who already have a child with a genetic disorder
- couples who have a family history of any inherited genetic condition
PGT-M cannot be used for gender selection in Malaysia.
FAQ about Karyomapping
How does Karyomapping differ from other PGT-M tests?
Until recently, PGT-M tests for disorders caused by inheritance of a defective gene had to be tailor-made for each couple. This required weeks or months of work by highly skilled scientists, meaning that costs were high and there was often a long wait before IVF treatment could begin. By contrast, karyomapping provides a test for PGT-M of almost any known gene defect with a rapid turnaround time. The accuracy of Karyomapping is improved as there are approximately 300,000 markers throughout the whole genome to determine the inheritance of the gene.
Who is Karyomapping for?
You may know that you are a carrier of a genetic disorder because you already have an affected child, or you may be aware of a family history of the disorder and have had your DNA tested.
Karyomapping is a new technique that allows couples, known to be carriers or affected with an inherited condition, to avoid passing on that disorder to their offspring. The technique works by screening embryos for the disorder before implantation in the womb (uterus)—a technique called Preimplantation Genetic Testing - Monogenic disorder, or PGT-M.
Using PGT-M greatly reduces the chance that a fetus will be affected by the genetic disorder and, consequently, it is much less likely that termination of a pregnancy will need to be considered, or that an affected child will be born.
Why IVF is needed?
In order to carry out PGT-M in vitro fertilization (IVF) is essential. This process involves collecting several eggs from the ovaries and fertilizing them outside the body (in vitro) to produce several embryos. Each of the embryos can then be tested to find out which are suitable for transfer.
Only the embryos that are predicted to be free of the genetic condition are transferred to the uterus and, consequently, any pregnancy that begins has a low risk of being affected by the disorder.
About Thalassaemia
Thalassaemia is an inherited blood disorder where due to the instability of the wall of the red blood cell (RBC), the patient constantly suffers from anaemia (low levels of haemoglobin, the oxygen carrying part of the RBCs).
- It is estimated that one in 20 Malaysians are thalassaemia carriers, which is about 1.5 million Malaysians, affecting mainly the Chinese.
- If both parents of a child are thalassaemia carriers, there is a 25% chance the child have major thalassaemia, which is a serious condition.
- PGT-M now offers a chance for the couple to have a disease free child by testing the embryos created from IVF for the thalassaemia gene before being implanted into the womb.
- This also effectively stops the thalasaemia gene from being passed down to the subsequent generations.