Preimplantation Genetic Testing for Monogenic Disorders (PGT-M)

Monash Biotech

March 2nd, 2025

In the world of assisted reproduction, Preimplantation Genetic Testing for Monogenic Disorders (PGT-M) stands as a groundbreaking tool for embryologists.

🔬 This advanced genetic screening method ensures that embryos carrying single-gene disorders—such as cystic fibrosis or sickle cell anemia—are not transferred, significantly reducing the risk of passing on inherited diseases. For embryologists, understanding PGT-M is crucial for offering patients the best chance of a healthy pregnancy.

What is PGT-M ?

PGT-M (formerly known as PGD—Preimplantation Genetic Diagnosis) is a specialized genetic test performed on embryos during in vitro fertilization (IVF). It screens for monogenic disorders, which are diseases caused by mutations in a single gene. Unlike PGT-A, which checks for chromosomal abnormalities, PGT-M focuses on detecting specific genetic mutations inherited from one or both parents.

Why is PGT-M Important? 🤔

• Prevents Transmission of Genetic Diseases ✅

• Increases the Chances of a Healthy Baby 👶

• Reduces the Emotional and Financial Burden of Genetic Conditions 💰

• Provides Reproductive Confidence for Carrier Parents 🧑‍⚕️

How PGT-M Works ? 🏗️

PGT-M is a multi-step process requiring precision and expertise:

1️⃣ Genetic Testing of Parents 🧬

• Blood or saliva samples from the intended parents are analyzed to identify the specific genetic mutation.

• A customized genetic probe is developed to detect the mutation in embryos.

2️⃣ IVF and Embryo Biopsy 🥚➡️🧪

• Eggs are fertilized through IVF, and embryos are cultured to the blastocyst stage (Day 5 or 6).

• A few cells are carefully biopsied from each embryo without harming its development.

3️⃣ Genetic Screening 🔬

• The biopsied cells undergo advanced genetic analysis to identify embryos that carry, are affected by, or are free of the mutation.

4️⃣ Embryo Selection & Transfer 👶

• Only mutation-free or carrier embryos (depending on parental preference) are selected for implantation, increasing the likelihood of a healthy pregnancy.

Who Needs PGT-M ? 🤷‍♂️

PGT-M is recommended for: ✅ Couples with a family history of genetic disorders ✅ Carrier parents of autosomal recessive or dominant conditions ✅ Patients with X-linked diseases like Duchenne Muscular Dystrophy ✅ Couples with prior affected pregnancies or children

PGT-M vs. Other Genetic Tests ⚖️

Common Monogenic Disorders Screened with PGT-M 🔍

Here are some genetic conditions that can be detected with PGT-M:

• Autosomal Recessive Disorders (Both parents must be carriers)

  • Cystic Fibrosis

  • Sickle Cell Anemia

  • Tay-Sachs Disease

• Autosomal Dominant Disorders (Only one parent needs the mutation)

  • Huntington’s Disease

  • Marfan Syndrome

  • BRCA1/BRCA2-Related Cancers

• X-Linked Disorders (Primarily affect males)

  • Hemophilia

  • Duchenne Muscular Dystrophy

  • Fragile X Syndrome

Benefits & Limitations of PGT-M 🚀🔬

✅ Benefits:

✔️ Reduces the risk of passing on serious genetic conditions

✔️ Provides peace of mind to carrier parents

✔️ Increases IVF success rates by selecting the healthiest embryos

✔️ Prevents the need for pregnancy termination due to genetic disease

⚠️ Limitations:

❌ Does not guarantee pregnancy success (Embryo quality and implantation factors still matter)

❌ Some diseases have incomplete penetrance (Mutation carriers may not always develop the disease)

❌ Requires advanced lab expertise and technology

What's the 🔮 Future of PGT-M ?

With advancements in whole-genome sequencing, CRISPR gene editing, and AI-driven embryo analysis, PGT-M will become even more accurate, accessible, and affordable. As the field of reproductive genetics evolves, embryologists will play a crucial role in guiding patients through these cutting-edge options.

PGT-M is a game-changing tool for preventing the inheritance of life-altering genetic diseases. For embryologists, mastering PGT-M means offering patients the opportunity to build healthy families with confidence. With ongoing technological advancements, PGT-M will continue to reshape the future of reproductive medicine. 🌍💙