PGT-M

Preimplantation genetic testing (PGT) is a broad term for a range of scientific techniques available during IVF to identify genetic abnormalities in embryos before they are transferred into the uterus.

PGT may be requested by couples or individuals who are at risk of passing on a genetic condition or structural chromosome rearrangement to their offspring. PGT may also be used to assess the number of chromosomes in an embryo.

PGT-M is a genetic test for your embryo designed to check for a known monogenetic or single-gene condition in your family, such as cystic fibrosis or spinal muscular atrophy. It can reduce the chance of a child being affected by a genetic condition.

Preimplantation genetic testing for monogenic or single-gene conditions (PGT-M) was previously called preimplantation genetic diagnosis (PGD).

Yes, it is possible to perform both preimplantation genetic testing for aneuploidies (PGT-A) and preimplantation genetic testing for monogenic or single-gene conditions (PGT-M) on the same embryo.

In fact, performing both PGT-A and PGT-M on embryos can provide a more comprehensive evaluation of their genetic health. At Newlife IVF, embryos are first tested for PGT-M. If no genetic defects are detected, embryos then undergo PGT-A.

Once an embryo (created as part of an IVF cycle) has reached the blastocyst stage (usually after 5–6 days of growth), a few cells are removed from the embryo. The cells obtained are then analysed using the PGT-M technique. Based on the results, your genetic counsellor and fertility specialist can advise which embryos are suitable to transfer into your uterus.

PGT-M allows couples and individuals to select embryos free of serious genetic conditions or single gene variants (associated with conditions such as cystic fibrosis or sickle cell anaemia), which reduces the risk of transmitting genetic conditions to children. This can give people peace of mind about conceiving healthy pregnancies, particularly for individuals or couples who have an increased risk of passing a genetic condition or single gene variant to their children.

PGT-M is a highly accurate screening test. However, it’s not without some limitations. For instance, not all embryos will reach the blastocyst stage needed for biopsy to perform PGT-M. Occasionally, an embryo will not survive the process of a biopsy. Further to this, the lab may not obtain a result for every embryo biopsied, and there is also a small potential for a false positive or false negative result.

PGT-M can be combined with other forms of preimplantation genetic testing, such as preimplantation genetic testing for aneuploidy (PGT-A) or preimplantation genetic testing for structural rearrangements (PGT-SR). PGT-A, which screens for chromosome abnormalities in embryos, is included for all patients having PGT-M. Meanwhile, PGT-SR screens for structural chromosome rearrangements (such as translocation*) and is an option for individuals or couples with an increased risk of passing an unbalanced chromosome rearrangement to their offspring.

^{*Translocation is a genetic change in which a piece of one chromosome breaks off and attaches to another chromosome.}

After PGT-M, embryos identified as free of the specific genetic condition or single gene variant are selected for transfer into the uterus. Any remaining embryos affected by the genetic condition will be discarded. Genetic counselling sessions are available to discuss the implications of the PGT-M results.