Preimplantation Genetic Testing for Monogenic Disorders (PGT-M) is a specialised genetic screening technique used during IVF to test embryos for specific inherited single-gene conditions before they are transferred to the uterus. It allows couples who carry genetic mutations to have children free of a serious inherited disorder, without the need to consider termination of an affected pregnancy.
PGT-M requires careful preparation in advance of an IVF cycle, including the design of a bespoke genetic probe specific to the couple's mutation. This preparatory work typically takes 2–3 months.
"PGT-M offers couples carrying serious genetic conditions the possibility of a healthy pregnancy — giving informed choice where it matters most."
Conditions That PGT-M Can Test For
PGT-M can be used to screen for hundreds of single-gene disorders. The most commonly tested include:
Autosomal Recessive
Sickle cell anaemia, cystic fibrosis, beta-thalassaemia, spinal muscular atrophy (SMA), Tay-Sachs disease. Both parents carry one copy of the faulty gene.
Autosomal Dominant
Huntington's disease, BRCA1/BRCA2 mutations, myotonic dystrophy, Marfan syndrome. Only one copy of the mutation is needed to pass on the condition.
X-Linked Disorders
Duchenne muscular dystrophy, haemophilia A and B, Fragile X syndrome. Carried on the X chromosome; often affects males more severely.
Mitochondrial Disorders
In selected cases, PGT-M can reduce the risk of transmitting certain mitochondrial conditions, though referral to specialist centres may be required.
Who Is PGT-M Recommended For?
Couples Who May Benefit from PGT-M
- Couples where both partners are known carriers of an autosomal recessive condition (e.g. sickle cell disease, thalassaemia, cystic fibrosis)
- One partner carries an autosomal dominant mutation with serious health implications
- Carriers of X-linked conditions such as Duchenne muscular dystrophy or haemophilia
- Couples who have previously had a child affected by a monogenic disorder
- Individuals who have had genetic testing confirming they carry a hereditary mutation with significant risk of transmission
- Couples who would find prenatal diagnosis (amniocentesis/CVS) and potential termination emotionally or ethically unacceptable
The PGT-M Process
Genetic Counselling
Before PGT-M is undertaken, both partners attend genetic counselling. The specific mutation(s) are confirmed and implications for the couple and any children are discussed.
Probe Design (Work-Up)
A specialist genetics laboratory designs a bespoke test — or "probe" — specific to your mutation. This preparatory phase typically takes 8–12 weeks and requires DNA samples from both partners and sometimes family members.
IVF and Embryo Biopsy
Once the probe is ready, you proceed with an IVF cycle. Embryos reaching the blastocyst stage are biopsied and the cells are sent to the genetics laboratory for analysis.
Results and Transfer
Results identify which embryos are unaffected, carriers, or affected. Unaffected embryos are selected for transfer. Carrier embryos (for recessive conditions) are generally healthy and may also be considered for transfer.
Speak to our team about PGT-M
If you or your partner carry a genetic condition, we can guide you through whether PGT-M is appropriate and what to expect at every stage of the process.
Book a Consultation