PGT-SR – Preimplantation Genetic Testing For Chromosomal Structural Rearrangement

What are chromosomal rearrangements?

Chromosomal rearrangements are any changes in the size or arrangement of chromosomes. Different types of chromosomal rearrangements include:

  • Deletions: in which a segment of a chromosome is missing
  • Duplication: in which there is an extra segment of a chromosome
  • Insertion: where a segment of a chromosome has been inserted into the incorrect location
  • Reciprocal Translocations: in which segments of two chromosomes break off and swap places
  • Robertsonian Translocations: in which segments of two chromosomes break off and join together to form one large chromosome, resulting in overall chromosome count of 45 instead of 46.
  • Inversions: in which a segment of a chromosome has reversed orientation

Who is it for?

Individuals who carry any of the above chromosomal rearrangement in the chromosomes are called balanced translocation or inversion carriers. Balanced translocation or inversion carriers have all the correct genetic information in their chromosomes; but some sections of the genetic material are found in a different position that expected. These individuals are generally healthy; however, they are at increased risk of having fertility problems, miscarriage, stillbirth and/or having a child with chromosomal abnormality due to the unbalanced form of their rearrangement.

 

How it works?

PGT-SR is a test to identify embryos with the correct amount of genetic material (balanced/normal) and embryos that have extra or missing genetic material as a result of the translocation or rearrangement (unbalanced). PGT-SR reduces the chance of a failed implantation or miscarriage, or of having a child with chromosomal abnormality, and increase the likelihood of a healthy pregnancy after an IVF cycle.

In ALPHA IVF, we can now distinguish between balanced and normal embryos. This enables transferring embryo without any chromosomal rearrangement carrier, thus preventing the future generations to carry the chromosomal rearrangement.