What Does Preimplantation Genetic Testing for Chromosomal Structural Rearrangements (PGT-SR) Mean?
Preimplantation genetic testing for chromosomal structural rearrangements (PGT-SR) is a genetic test designed to ensure a pregnancy that is not impacted by any changes in the size, position, or structure of chromosomes (known as chromosomal structural rearrangements) in a couple with a chromosomal rearrangement.
Chromosomes are tightly coiled structures that enclose genetic material. Any chromosomal rearrangement can mean that the embryos do not have the correct genetic information that is required to lead to a successful pregnancy.
PGT-SR was formerly known as preimplantation genetic testing (PGT).
FertilitySmarts Explains Preimplantation Genetic Testing for Chromosomal Structural Rearrangements (PGT-SR)
Chromosome rearrangements can be hereditary or can spur spontaneously. Similarly, they can be balanced or unbalanced.
Balanced chromosomal rearrangements have the entire set of genes. However, part of a chromosome breaks off and moves to another site. Most people with balanced chromosome rearrangements are healthy and do not know that they carry such an alteration until they try to conceive. But, when they plan a pregnancy, they have a risk of passing an “unbalanced” rearrangement to their child. An unbalanced rearrangement is one where a piece (s) of chromosomes is either missing or duplicated, resulting in miscarriages or children with learning problems, developmental delays, or other health problems.
In such cases, PGT-SR can be performed to boost the odds of conceiving a healthy baby. Just like other types of PGT, PGT-SR involves testing cells from embryos as part of an in vitro fertilization (IVF) process and only transferring the normal ones.