Preimplantation genetic testing of embryos for the detection of PGT-A aneuploidy (PGS)

At Invimed, preimplantation genetic testing for the detection of aneuploidies in embryos, formerly called: preimplantation genetic screening of embryos (preimplantation genetic screening - PGS), are performed using the advanced Next Generation Sequencing (NGS) technique. It allows a detailed reading of the entire genome of the embryo for the study of structural and numerical abnormalities of chromosomes (aneuploidy).

How does the PGT-A test work?

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Stage 1 Biopsy

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Stage 2: Genetic testing

Stage 1 Biopsy

Biopsy of the embryo takes place on day 5 of development, at the blastocyst stage. An experienced embryologist takes a few cells of the trophoectoderm of the embryo. He then secures the collected material and sends it for genetic analysis. Embryos that have undergone PGT-A are vitrified (frozen).

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Stage 2: Genetic testing

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Stage. 3. embryo evaluation

Stage 2: Genetic testing

 

In the genetics laboratory, genetic material (DNA) is isolated from harvested embryo cells and analysed using a sequencer using NGS technology.

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Stage. 3. embryo evaluation

Stage. 3. embryo evaluation

 

After receiving the results of the genetic test, the doctor together with the embryologist decide which genetically normal embryos can be intended for transfer.

Biopsy of the embryo does not affect its normal development. The risk of the embryo stopping further development is only 0.53%.

NGS sequencing, which is used for PGT-A genetic testing, is a state-of-the-art technique that allows rapid analysis of the entire genome of an embryo, thanks to so-called parallel sequencing, which is the reading of the nucleotide sequence of a DNA molecule.

What does the PGT-A test detect?

PGT-A testing detects structural and quantitative changes in chromosomes. 

Any abnormalities in the number and structure of chromosomes can cause embryonic malformations and result in genetic diseases, i.e. Down syndrome (an excess of genetic material in the form of the presence of an extra third chromosome 21 or part of it called trisomy 21, or Patau syndrome (trisomy of chromosome 13).

How to provide the doctor with the test results?

In the case of consultations with a gynaecologist (as part of the initial infertility consultation) and an immunologist, the teleportation takes place on the basis of a history and medical records provided by the patient.

• Wolf-Hirschhorn syndrome

• Di George syndrome

Structural aberrations (e.g. translocations) may be responsible for the occurrence of cancer, among other diseases.

Genetic diseases caused by aneuploidy (incorrect karyotype in terms of number of chromosomes):

• Kinefellter syndrome,

• Jacobs syndrome,

• band XXX,

• Turner syndrome,

• Down's syndrome,

• Edwards syndrome,

• Patau syndrome,

• Warkany syndrome 2.

For more on diseases associated with an abnormal karyotype, see the subpage: Karyotype.

When to perform the PGT-A test?

PGT-A testing is recommended primarily for couples:

• who have had habitual (recurrent) miscarriages,

• having a child with a genetic disorder (e.g. Down's syndrome),

• in which an abnormal karyotype has been detected in one or both of them,

• whose partner has a poor semen test result, particularly an abnormal test result SCD (sperm DNA fragmentation),

• when a woman has exceeded the age of 35.

Where to perform PGT-A testing of embryos?

PGT-A testing is performed in every Invimed clinic. Invimed clinics cooperate with the largest genetic laboratory located in Europe - Igenomix . A team of eminent internationally recognised scientists has headed Igenomix for more than a dozen years. Igenomix has the largest gene libraries, as well as top-of-the-range NGS sequencers.