Preconception genetic testing usually includes:
- Clinical genetic examination – analysis of personal and family history of both partners by means of a genetic consultation.
- Chromosomal examination of both partners.
- In indicated cases in women, examination of predispositions for increased blood clotting – thrombophilic conditions (FV Leiden mutation and mutations of the FII prothrombin gene).
- Screening for hidden carrier status of the most common inherited diseases – in our population, these are mainly cystic fibrosis (CF) and spinal muscular atrophy (SMA), but in addition to these, it is also possible to detect carrier status of other rarer diseases that may affect the offspring’s senses (e.g. hearing impairment) or metabolism (inborn metabolic diseases).
- In men with a severe spermiogram disorder, examination of the loss (microdeletion) of material on the Y chromosome (azoospermic factor – AZF).
According to the results of the preconception examination, it is possible to suggest the optimal course of treatment with assisted reproduction methods, decide on the suitability of preimplantation genetic testing (PGT) and plan the care of future pregnancies (prenatal diagnostics).
Preimplantation genetic testing (PGT)
Within the framework of assisted reproduction methods, it is possible to perform genetic testing and selection of embryos formed in a test tube before the transfer to the uterus, i.e. preimplantation.
The method of testing is based on the conclusions of the genetic consultation. Preimplantation testing can either be focused at diseases already present in the family or at random genetic changes due to the external environment or the age of the parents.
PGT-A: Preimplantation genetic testing for aneuploidies
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- examination of embryos to exclude newly formed chromosome defects
PGT-SR: Preimplantation genetic testing for structural chromosomal defects
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- is suitable for couples where one or both partners are found to carry a balanced translocation or other structural chromosomal rearrangement.
PGT-M: Preimplantation genetic testing for monogenic diseases
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- is intended for couples with a known risk of transmitting a serious genetic disease (monogenically inherited diseases such as cystic fibrosis (CF), spinal muscular atrophy (SMA), etc.)
PGT-A testing in indicated patients is performed at our department for the cooperating ART Sanatorium.
The aim is to reduce the risk of implantation of an embryo with an unbalanced chromosomal aberration or chromosomal aneuploidy (missing or supernumerary chromosome), which would lead to a failure of the IVF cycle, or to the decision to artificially terminate the pregnancy; or a male embryo that has a high risk of manifesting a disease linked to the X sex chromosome if the mother is a carrier.