IVF Zentren Prof. Zech - Pilsen

← Genetics

PGT-SR

Preimplantation Genetic Testing for familial Structural chromosomal Rearrangement (older name PGD: Preimplantation Genetic Diagnosis of familial chromosomal aberration)

Preimplantation genetic testing of familial chromosomal aberrations/rearrangements (PGT-SR) is a targeted diagnosis of unbalanced forms of family specific chromosomal abnormalities which may cause birth of a disabled child or repeated pregnancy losses. This examination is always performed only upon indication of a clinical geneticist after careful evaluation of the family history.

Indications for examination:

  • Carriage of so called balanced chromosomal rearrangement (usually translocation) in one or both partners.
  • The presence the numerical changes in sex chromosomes (gonosomes) including the mosaic form in one or both partners.

Examined tissues:

The examination is usually performed on the cells of the trophectoderm extracted on the 5-6th day of the embryo development, but in some special cases it can be performed also on blastomeres or polar bodies.

Examination Methods:

Currently we perform PGT-SR using Next Generation Sequencing (NGS) or by Fluorescent in situ Hybridization (FISH).

PGT-SR using the NGS method enables examination of the unbalanced forms of familial chromosomal rearrangement of larger extent and a screening of quantitative changes in other chromosomes at the same time (PGT-A).

PGT-SR using the FISH method is used only for the PGT-SR of unbalanced forms of familial structural rearrangements of a smaller extent in which the NGS method cannot be used.

Therapy:

If you choose to undergo the therapy with preimplantation genetic testing its course will be similar to the "regular" IVF-ICSI treatment. The only difference is that the biopsy (extraction of several trophectoderm cells) is performed on the 5-6th day of the embryo development. The embryonal material is then analysed in the genetic laboratory and the biopsied embryos are vitrified. As soon as the results of the genetic testing are available the IVF-ICSI therapy goes on and ends with the transfer of a healthy embryo.