PGT‑M for Single‑Gene Conditions

PGT-M (Preimplantation Genetic Testing for Monogenic diseases) is a highly targeted test that checks embryos for a specific inherited condition—such as cystic fibrosis, thalassemia, spinal muscular atrophy, Huntington’s disease, or a known familial mutation.

PGT-M:

• Identifies which embryos carry or are affected by your known mutation
• Does not test for all genetic issues (that’s PGT-A or carrier screening)
• Does not repair embryos—it only sorts them
• Requires a custom test (“family probe”) made from your DNA

Where it fits:

• Always used within an IVF cycle
• Best applied when avoiding transmission of a known genetic disease is the primary goal
• Upstream choices—like detailed family history, DNA samples, and lab timing—shape downstream accuracy and speed

Who It Helps

Signals of Good Fit vs When to Consider a Different Path

Good Fit Signals

PGT-M is strongly indicated when:

• You or your partner are carriers of the same autosomal recessive condition
• One partner has an autosomal dominant condition with a 50% transmission risk
• There is a known familial mutation confirmed on genetic testing
• You want to avoid late-onset conditions present in your family
• You already plan IVF for other reasons and want precise embryo selection

Possible Poor Fit or Gray Zones

PGT-M may be less suitable when:

• The familial mutation is not yet identified
• There is insufficient DNA from affected relatives to build a probe
• You expect very few embryos (low ovarian reserve, age >42) and testing may not change your decision
• The condition has variable expression and family decisions are more nuanced
• Timing is tight—building the custom assay can take 4–12 weeks

This section can integrate AMH, AFC, semen parameters, and previous response to shape realistic expectations.

Step-by-Step

A Simple Sequence With Timing Checkpoints

1. Genetic Counseling + Confirmatory Testing
   – Verify the exact mutation, gather family DNA, and define inheritance pattern.

2. Probe Development (Custom Assay Creation)
   – Lab builds a family-specific test.
   – Timeframe: ~4–12 weeks depending on complexity and availability of samples.

3. IVF Stimulation & Egg Retrieval
   – Plan focuses on maximizing healthy, mature oocytes.

4. Fertilization (IVF/ICSI)
   – ICSI is usually recommended to avoid contamination.

5. Embryo Culture to Day 5–7
   – Only blastocysts are eligible for biopsy.

6. Trophectoderm Biopsy + Freeze
   – Cells are sent to the genetics lab; embryos remain frozen.

7. PGT-M Analysis (2–3 weeks)
   – Results classify embryos as unaffected, carriers, or affected.

8. Transfer Planning
   – Unaffected embryos prioritized; discuss carrier options depending on the condition.

Timing checkpoints help protect embryo quality and reduce unnecessary stress.

Pros & Cons

Balanced View of Benefits, Trade-offs, Risks, and Realistic Expectations

Pros

• Dramatically reduces the chance of having a child with the targeted condition
• Allows confident selection of unaffected embryos
• Avoids complex prenatal decision-making later
• Often combined with PGT-A if age-related risks are also a concern
• Helps families with severe or life-limiting conditions plan safely

Cons / Trade-offs

• Requires IVF (even if you don’t have infertility)
• Probe development adds time and cost
• Not all families have enough DNA for accurate probe creation
• False negatives are rare but possible
• Each biopsy adds handling risk
• May yield few or no unaffected embryos, requiring multiple cycles

Costs & Logistics

Preventing Surprise Bills

Typical cost components:

• Probe development fee (one-time, often the biggest expense)
• Biopsy fee per embryo
• Test panel charges (PGT-M ± PGT-A)
• Courier charges for samples
• Embryo storage fees
• Follow-up consults

Practical planning tools:

• Check whether your insurer requires prior authorization
• Use a cycle cost tracker to track charges in real time
• Ask if your clinic bills per embryo or per batch
• Understand cancellation policies if probe development fails
• Plan cash-flow across expected multiple cycles if embryo numbers may be low

What Improves Outcomes

Actions That Materially Change Results

High-impact actions:

• Optimizing stimulation protocols for maximum mature eggs
• Ensuring clean DNA samples for probe creation
• Using ICSI to reduce contamination
• Choosing an experienced genetics lab familiar with your condition
• Reviewing biopsy criteria and thresholds beforehand
• Managing expectations around the number of unaffected embryos

Low-impact or low-yield actions:

• Excess supplements without evidence
• Testing embryos with poor morphology unlikely to implant
• Repeating biopsies without a compelling reason
• Assuming PGT-M and PGT-A replace good prenatal screening—they don’t

Case Study

From Uncertainty to Clarity Through Defined Thresholds

A couple carried the same recessive mutation for beta-thalassemia. They feared passing it on but were anxious about IVF and testing timelines.

Through:

• Early consult with a genetic counselor
• Gathering DNA from an affected sibling to build a strong probe
• Setting thresholds (“Proceed with PGT-M only if ≥4 blastocysts are available”)
• Weekly timeline check-ins
• Pre-defined policies for what to do if only carrier embryos were available

They moved from uncertainty to a structured plan. Two unaffected embryos were identified, and a single-embryo transfer led to a healthy pregnancy—without surprise costs or last-minute decisions.

Mistakes to Avoid

Common Traps + Simple Fixes

• Starting IVF before probe development is ready
• Not confirming who pays for lab shipping or storage
• Assuming one cycle will yield enough unaffected embryos
• Forgetting to discuss carrier embryos and future family planning
• Underestimating timeline delays when family DNA is missing
• Expecting PGT-M to screen for everything—it’s mutation-specific

FAQs

Q. Does PGT-M guarantee an unaffected baby?

Ans : No, but it greatly reduces risk and is highly accurate when the probe is well-designed.

Q. Can we skip IVF and test during pregnancy instead?

Ans : Prenatal testing is an option, but PGT-M helps avoid difficult decisions later.

Q. How long does probe development take?

Ans : 4–12 weeks depending on mutation complexity and available family samples.

Q. Do we need to test all embryos?

Ans : Yes—PGT-M is mutation-specific and each embryo may differ.

Q. Should we add PGT-A?

Ans : Depends on age and embryo count; many clinics offer combined testing for patients 35+.

Next Step

• Free 15-min nurse consult
• Upload your labs for a personalized review
• Receive a customized cost breakdown for your case

Related Links

• Genetic testing carrier
• Intended Parents
• Become a Surrogate
• Fixed‑Cost Packages
• SART
• CDC ART
• ASRM