Pre-implantation Genetic Testing for Monogenic Disorder (PGT-M)

Pre-implantation Genetic Testing for Monogenic Disorder (PGT-M) is an advanced genetic test used during IVF to identify embryos carrying specific inherited genetic disorders.

PGT-M focuses on single-gene disorders, which are diseases caused by mutations in a single gene passed down from parents to children.

During the IVF process, a small number of cells are carefully biopsied from the embryo and analysed in our genetic laboratory. This allows our genetic scientists and fertility specialists to determine whether the embryo carries the genetic condition.

Only embryos that are not affected by the targeted genetic disorder are selected for transfer, helping increase the chance of having a healthy baby.

At Sunfert, to perform PGT-M accurately, we use a technology known as Karyomapping. This advanced and innovative approach allows us to examine an embryo’s DNA in detail, helping us identify embryos that are free from specific inherited genetic disorders while also checking for chromosomal normality.

During the PGT-M process, a few cells are biopsied from the embryo and analysed. Karyomapping traces the inheritance of DNA segments from both parents to detect whether the embryo has inherited specific genetic mutations that could cause monogenic disorders, such as Cystic Fibrosis or Thalassemia. At the same time, the embryos are also screened for chromosomal abnormalities, such as Down’s syndrome or Patau’s syndrome using the same technology. 

With these results, we can then select embryos that are both chromosomally normal and free from the inherited genetic disorders - improving the chances of a successful implantation, supporting a healthier pregnancy, and reducing the risk of miscarriage or inherited disease for patients undergoing IVF.

There are many other genetic disorders known worldwide and here are some common ones in Asia.

• Thalassaemia
• Cystic Fibrosis
• Huntington’s disease
• Spinal Muscular Atrophy (SMA)
• Certain inherited metabolic or neurological disorders

PGT-M provides couples who are carriers of genetic disorders with an opportunity to reduce the risk of passing the disorder to their children.

PGT-M may be recommended for individuals or couples who have a known risk of passing a genetic condition to their child.

You may benefit from PGT-M if:

• you and/or your spouse are carriers of a known genetic disorder
• you and/or your spouse are affected by a genetic disorder
• you already have a child affected by a genetic condition
• you have ended a previous pregnancy because of a genetic condition
• there is a family history of inherited disease
• genetic carrier screening tests have identified a risk of specific monogenic disorders
• you want to reduce the risk of transmitting a hereditary condition during IVF
• you want to perform HLA matching

Couples who are carriers of genetic disorders, such as Thalassaemia, are often advised to consider PGT-M when planning a pregnancy.

Step 1: Expanded Carrier Screening

Blood samples are taken from the couple for Expanded Carrier Screening (ECS) which is a genetic test to check if the couple are carriers of certain genetic conditions. This screening can help to reveal the couple’s risks of having a child with inherited genetic disorders. After the results are ready, the couple will undergo a genetic counselling session to discuss the results and if PGT-M is required. 

If the couple already has their ECS test results or other genetic testing reports, the clinician or genetic counsellor will review the results and advise if further testing is required. 

Step 2: IVF Treatment & Embryo Development

We stimulate the ovaries, retrieve the eggs, and fertilise them in our laboratory through IVF/ICSI.

The embryos are cultured until they reach the blastocyst stage (Day 5 or Day 6).

Step 3: Embryo Biopsy

Performed by our highly-trained embryologists and genetic scientists, a tiny cluster of cells is collected from the outer layer of the blastocyst (trophectoderm biopsy).

This procedure is performed by our experienced genetic scientists with precision to minimise any impact on embryo development.

Step 4: Pre-implantation Genetic Testing for Monogenic Disorder

The DNA from the embryos is used to determine if the embryos had inherited normal and/or affected copies of the gene. This is done by comparing single nucleotide polymorphisms (SNPs) of the embryo and the couple, diagnosing each embryo as affected, unaffected or a carrier of the genetic condition.

At the same time, the embryos are also checked if they have a normal number of chromosomes.

Step 5: Embryo Selection and Transfer

Only embryos that are not affected by the genetic disorder are selected for transfer into the uterus.
 

If you are facing fertility challenges, start with a consultation at Sunfert. We will guide you through your fertility journey with expertise and compassionate care. 

Make an appointment with our Fertility Specialist today and take the next step toward your parenthood goals.

Question #1: Is PGT-M the same as PGT-A?

• No. PGT-M tests for specific inherited genetic disorders caused by mutations in a single gene, while PGT-A screens for chromosomal abnormalities in embryos.

Question #2: Does PGT-M guarantee a healthy baby?

• PGT-M significantly reduces the risk of passing specific genetic disorders, giving the baby a better start in life.

Question #3: Is embryo biopsy safe?

• Embryo biopsy requires a tremendous amount of training and years of experience, supported by a well-established procedure.
• At Sunfert, we ensure that all our embryologists and genetic scientists are well-trained and strictly follow established protocols. Hence, we are confident that the biopsy procedures performed at Sunfert are safe for patients’ embryos.

Question #4: Do all IVF patients need PGT-M?

• No. PGT-M is mainly recommended for couples with known genetic risks or inherited disorders.

Question #5: How do I know whether my spouse or I have inherited any genetic disorders?

• If patients are unsure whether they carry certain inherited genetic disorders, they can undergo Expanded Carrier Screening (ECS). This test helps identify whether an individual carries a gene associated with specific inherited disorders.
• In some cases, a person may be asymptomatic (showing no symptoms) and may therefore be unaware that they are a carrier. However, the gene can still be passed on to their children.
• For certain inherited genetic disorders, such as Thalassaemia, a baby may be affected if both partners are carriers. In other disorders, such as Huntington’s disease, only one parent needs to carry the gene for the baby to be at risk of inheriting the disorder.