PGD, PGS, NGS, PGT in Tbilisi, Georgia IVF Center Atlas

PGD, PGS, NGS, PGT in Tbilisi, Georgia IVF Center Atlas: A Guide

If you've started researching IVF, you've likely come across a cluster of overlapping acronyms PGD, PGS, PGT, and NGS often used almost interchangeably, even though they refer to distinct concepts. Our clinic in Tbilisi offers genetic testing for embryos using modern NGS technology, and we believe understanding these terms clearly helps patients make more informed decisions about their treatment.

Clearing Up the Terminology

PGT (Preimplantation Genetic Testing) is the current umbrella term used in clinical practice to describe genetic testing performed on embryos before transfer. It replaced the older, separate terms PGD and PGS, which are still commonly used in casual conversation but have technically been folded into more specific PGT subcategories.

PGD (Preimplantation Genetic Diagnosis), now more precisely referred to as PGT-M (M for "monogenic"), refers to testing for a specific, known genetic disorder that runs in a family such as cystic fibrosis, Huntington's disease, or a hereditary form of cancer. This type of testing is used when parents already know they carry a particular disease causing mutation and want to avoid passing it on.

PGS (Preimplantation Genetic Screening), now referred to as PGT-A (A for "aneuploidy"), refers to a broader screening of embryos for the correct number of chromosomes, rather than testing for one specific condition. This is the most commonly requested form of genetic testing, particularly for women of advanced maternal age or those with a history of recurrent miscarriage or failed IVF cycles.

There's also PGT-SR (structural rearrangement), used when a parent carries a chromosomal rearrangement, such as a translocation, that doesn't cause them health issues but can lead to embryos with unbalanced chromosome structures.

NGS (Next Generation Sequencing) isn't a type of genetic test in itself it's the underlying laboratory technology used to perform PGT-A, PGT-M, and PGT-SR. NGS has largely replaced older methods because it allows for faster, more accurate, and more detailed analysis of embryonic cells, including the ability to detect a broader range of chromosomal abnormalities in a single test.

How Testing Works in Practice

Regardless of which type of PGT is used, the underlying process is similar. Embryos are cultured in the laboratory to the blastocyst stage typically day 5 or 6 at which point a small number of cells are carefully biopsied without harming the embryo. These cells are sent for NGS based genetic analysis, with results usually available within a few days. Only embryos identified as chromosomally normal, and free of the relevant condition where PGT-M or PGT-SR applies, are considered for transfer.

Who Typically Benefits Most

Genetic testing is generally recommended for women of advanced maternal age, couples with a known hereditary condition in the family, patients with a history of recurrent pregnancy loss, and those who have experienced previous unsuccessful IVF cycles. A genetic counseling consultation is available to help determine which form of testing, if any, is appropriate for your specific situation.

If you have questions about how PGT could apply to your treatment plan, our team in Tbilisi is glad to walk you through the options in detail.