PGT-M Preimplantation Genetic Testing for Monogenetic / Single Gene Conditions

Preimplantation Genetic Testing for Monogenic Disorders (PGT-M) is a genetic test to analyze embryos before implantation for many types of inheritable disorders caused by single gene mutations.

These include autosomal dominant conditions from either partner, such as Huntington’s Disease, or Myotonic Dystrophy or when the female partner is a carrier of an X-linked condition such as Cystic Fibrosis or Sickle Cell anemia; and also sex-linked conditions such as Duchenne’s Muscular Dystrophy, and many other disorders.

Our Monash IVF genetic counselling team is available to consult with you and discuss your reproductive options, including the consideration for preimplantation genetic testing.

The Ministry of Health in Singapore announced on 4 May 2021 the introduction of pre-implantation genetic testing for monogenic / single gene defects (PGT-M) as regulated clinical services. PGT-M uses Polymerase Chain Reaction (PCR)-based single cell tests for genetic diseases and conditions. Visit the Ministry of Health website for a full list of genetic conditions.

Who should receive PGT-M?

Parents who may be at an increased risk of carrying a child with a monogenic disorder often choose to undergo this test. Those at a higher risk include parents diagnosed with a monogenic disorder, parents who are carriers of or have a known family history of a monogenic disorder of, or parents who already have a child with a monogenic disorder.

As always, it is important to discuss your options with your fertility specialist who can guide you through the process (and regulatory landscape in Singapore) and loved ones and make the best, well-informed decision for your family.

Testing for PGT-M

PGT-M testing is performed on embryos during IVF and other assisted reproductive treatments and is used to screen potential embryos and select those without the tested mutations for implantation.

Through “karyomapping”, an advance method of testing embryos, DNA fingerprinting technology is applied to identify which embryos have inherited the genetic variant known in the family. Embryos which have been grown to Day 5 have cells removed from the outside layer of the embryo (“embryo biopsy”) and the cells are sent our lab for testing. The test can also identify common chromosome changes which impact on the chance of implantation and miscarriage.

What can I expect from the PGT-M Process?

Before PGT-M can be done, perspective parents must attend a consultation with their physician or fertility specialist to assess the risk of their embryos containing certain mutations. If the parents choose to undergo the test, blood or saliva samples are taken from both parents and other family members if necessary.

A biopsy is then taken from each perspective embryo (grown to Day 5) and sent for DNA analysis. Results will indicate a presence (positive) or absence (negative) of a gene mutation. Those embryos testing negative for tested mutations will be selected for transfer.