PGT-M for Hereditary Conditions in Thailand: A Patient Guide

PGT-M (preimplantation genetic testing for monogenic disease) is a laboratory step used during IVF to test embryos for a specific inherited condition that is already known to run in a family. It is not a general health screen and it does not test for every possible disorder. It is designed around one condition, or a small number of conditions, identified in advance through genetic counselling and confirmatory testing. In Thailand, PGT-M is offered by some fertility clinics, but availability, laboratory arrangements and eligibility criteria vary. This guide explains the purpose of PGT-M, the kinds of conditions it may be used for, and the practical questions international patients should ask before planning treatment.

At a glance

• What it is: A targeted genetic test on embryos created through IVF, looking for a known inherited condition.
• What it is not: A guarantee of a healthy child, a general screening test, or a replacement for prenatal testing.
• Who it may suit: People with a confirmed family history or carrier status for a specific monogenic condition.
• Key first step: Genetic counselling and a clear genetic diagnosis before IVF is planned.
• In Thailand: Confirm that the clinic can build or access a test specific to your condition and that the laboratory is accredited for that work.

What PGT-M actually tests for

PGT-M is used when a specific gene change (a pathogenic variant) has been identified in a family. The test looks at embryos created through IVF to see whether they have inherited that variant. It is sometimes called monogenic disease testing because it targets conditions caused by a change in a single gene.

Examples of conditions that may be considered for PGT-M include cystic fibrosis, spinal muscular atrophy, thalassaemia, Huntington’s disease, fragile X syndrome, and some inherited cancer syndromes. This is not a complete list, and whether PGT-M is appropriate depends on the specific condition, the inheritance pattern, and the genetic information available from the family.

PGT-M is different from PGT-A, which counts chromosomes and is used more broadly. PGT-M is also different from PGT-SR, which looks at structural chromosome rearrangements. If you are researching PGT generally, it helps to keep these categories separate, because they answer different questions.

Which conditions may qualify for PGT-M

PGT-M is generally considered when all of the following apply:

• A specific inherited condition has been diagnosed in the family or confirmed through carrier testing.
• The gene or genes involved are known, and the laboratory can design a reliable test.
• The condition is serious enough that a family wishes to avoid passing it on, and other options have been discussed.
• Genetic counselling has taken place, so the patient understands the inheritance pattern and the limits of testing.

Conditions with a clear single-gene cause are the most straightforward to test for. Conditions caused by many genes plus environment, or by unknown genes, are generally not suitable for PGT-M. Some conditions also require a custom test to be built, which takes time and may not be available at every clinic.

Inheritance patterns matter

How a condition is inherited affects who may be at risk and what testing can show. Autosomal recessive conditions, such as cystic fibrosis or thalassaemia, require both partners to be carriers. Autosomal dominant conditions, such as Huntington’s disease, can be passed on by one affected parent. X-linked conditions, such as some forms of muscular dystrophy, have a different pattern. A genetic counsellor or clinical geneticist can explain which pattern applies to your family.

What the PGT-M process involves

The exact steps vary by clinic and by condition, but the general sequence is usually similar.

1. Genetic counselling and confirmation. A clinical geneticist or genetic counsellor reviews the family history and confirms the exact gene variant. This often requires a blood or saliva sample from the affected person or carrier.
2. Test development. The laboratory designs a test that can reliably detect that variant in a single cell or a few cells taken from an embryo. This step can take weeks or longer and may not be possible for every condition.
3. IVF cycle. Eggs are collected and fertilised in the laboratory to create embryos.
4. Embryo biopsy. A small number of cells are removed from each embryo, usually at the blastocyst stage.
5. Genetic analysis. The biopsy samples are tested for the specific variant.
6. Embryo transfer. An embryo that does not carry the variant may be selected for transfer, if one is available and suitable.
7. Prenatal testing. Even after PGT-M, many clinics recommend confirmatory testing during pregnancy, such as chorionic villus sampling or amniocentesis, because PGT-M is a screening test for embryo selection and not a diagnostic test of the pregnancy.

What to confirm with a clinic in Thailand

Because PGT-M is highly specific, the most important question is whether the clinic and its laboratory can actually test for your condition. General IVF experience is not the same as experience with a particular monogenic disease.

Questions worth asking:

• Have you handled PGT-M for this specific condition before?
• Do you build custom tests in-house, or do you send samples to an external laboratory?
• Which laboratory performs the analysis, and what accreditation does it hold?
• What genetic information do you need from my family before you can confirm the test is possible?
• How long does test development take, and what happens if the test cannot be built?
• What are the limitations of the test in my case, including the chance of an inconclusive result?
• Do you require genetic counselling before treatment, and can it be done remotely?
• What is your policy on confirmatory prenatal testing?
• What documents do international patients need to provide, and how are they verified?
• What are the estimated costs, and what is included or excluded?

Costs, document requirements and legal rules can change and vary between clinics. Treat any figure or requirement you see online as something to confirm directly with the clinic and, where relevant, with the appropriate authority.

Limitations and alternatives

PGT-M is not a guarantee. It reduces the chance of transferring an embryo with a specific known variant, but it cannot eliminate all risk. Some embryos may be mosaic, meaning the biopsy result may not reflect the whole embryo. Some tests may give an inconclusive result. And PGT-M does not screen for other genetic conditions, chromosomal issues, or health problems that appear later in life.

Alternatives to consider, depending on your situation, include:

• Using donor eggs or donor sperm.
• Prenatal diagnosis during pregnancy, with or without IVF.
• Preimplantation genetic testing for aneuploidy (PGT-A) or for structural rearrangements (PGT-SR), if those are more relevant to your case.
• Choosing not to have genetic testing and accepting the natural chance of inheritance.
• Adoption or fostering.

These are personal decisions, and a genetic counsellor can help you weigh them without pressure.

Planning as an international patient

If you are travelling to Thailand for PGT-M, plan for more than one trip in many cases. The first visit may be for consultation and blood samples; the IVF cycle and embryo testing happen later. Ask the clinic how results are communicated, what happens if no unaffected embryo is available, and how follow-up is arranged once you return home.

It also helps to have a clear summary of your genetic diagnosis in English, including the gene name, the specific variant, and the inheritance pattern. This document is often requested before a clinic can confirm whether PGT-M is possible.

Next steps

• Speak with a genetic counsellor or clinical geneticist about your family history.
• Obtain written confirmation of the exact gene variant.
• Shortlist clinics that have experience with your specific condition.
• Ask each clinic the questions above and compare their answers.
• Confirm costs, timelines, and document requirements directly.
• Read more about PGT in Thailand and browse our guides for related topics.

Frequently asked questions

Is PGT-M the same as PGT-A?

No. PGT-M looks for a specific inherited condition caused by a known gene variant. PGT-A counts chromosomes and is used to check for an abnormal number of chromosomes. They answer different questions and may be used together in some cases.

Can any clinic in Thailand offer PGT-M?

Not necessarily. PGT-M requires a laboratory that can build or access a test for your specific condition. Availability varies, so you should confirm directly with the clinic whether they can test for your condition and which laboratory performs the analysis.

Does PGT-M guarantee a healthy baby?

No. PGT-M reduces the chance of transferring an embryo with a specific known variant, but it cannot eliminate all genetic or health risks. It does not test for every condition, and confirmatory prenatal testing is often recommended.

What information do I need before asking a clinic about PGT-M?

You will usually need a clear genetic diagnosis, including the gene name, the specific variant, and the inheritance pattern. A genetic counsellor or clinical geneticist can provide this, often after reviewing family history and test results.

Are there alternatives to PGT-M?

Depending on your situation, alternatives may include using donor eggs or sperm, prenatal diagnosis during pregnancy, or choosing not to have genetic testing. A genetic counsellor can explain the options and their limitations.

Continue your research

• PGT in Thailand overview
• PGT and IVF guides
• Frequently asked questions

Medical information notice: This article is educational and does not replace individual assessment, diagnosis, genetic counselling or treatment advice from a licensed clinician. Provider services, availability, fees and policies should be verified directly before booking.