Reproductive genetics Gestamosurrogacy

Reproductive genetics

Reproductive genetics is a specialty that focuses on studying processes related to human reproduction, infertility, and the inheritance of genetic and chromosomal characteristics to offspring. This branch of genetics investigates aspects ranging from fertility and the genetic causes of infertility to advances in assisted reproductive technologies. It also plays a fundamental role in the identiﬁcation of inherited genetic diseases, constituting an integral part of the reproductive process.

Preconceptional genetics

Test for recessive disease carriers:

The genetic study of point gene mutations is a vital tool in risk assessment for transmitting certain genetic conditions to offspring. Most humans carry between two and four mutations in speciﬁc genes; therefore, this analysis is critical in determining whether a couple or a person using a gamete donor shares the same mutation in a particular gene. If they both share the same mutation, there is a signiﬁcant risk that their descendants will develop inherited diseases associated with that mutation.

Preimplantation genetics

Preimplantational genetic diagnosis (PGT)

Preimplantation Genetic Diagnosis (PGT) is a preventive strategy used in assisted reproduction. Its primary purpose is to detect anomalies in embryos' genetic material before their transfer to the maternal uterus. Thanks to this valuable technique, it is possible to avoid the transfer of embryos that present genetic or chromosomal alterations, which increases the probability of conceiving a healthy baby.

There are various kinds of PGT, among them are:

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PGT-A: Preimplantational Genetic Test for Aneuploids. This analysis can detect complete chromosomes that are extra or missing (trisomies or monosomies), chromosome fragments that are duplicated or with deletions (duplications or partial deletions), and mosaic embryos.

INVASIVE PGT (PGT-A)

It requires performing an embryonic biopsy with a laser, which consists of extracting 4 to 6 cells from the embryo's outer layer, called trophectoderm. These will be analyzed in a genetics laboratory while the embryo remains vitrified (frozen). The results will then be considered a diagnosis.

NON-INVASIVE PGT

NON-INVASIVE genetic analysis is a non-diagnostic study that examines the free DNA of embryonic origin present in the culture medium where the embryos developed. This approach avoids the embryo biopsy, thus minimizing the risk to the embryo. The main objective is prioritizing those embryos most likely to be euploid (chromosomally healthy) for transfer.

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PGT-M: Preimplantational genetic test for monogenic diseases. This test makes it possible to identiﬁcate the presence of speciﬁc genes that can cause hereditary diseases, ensuring that only embryos free of mutations associated with familial are apt to transfer. It is performed by analyzing cells obtained from the trophectoderm by embryo biopsy.

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PGT-SR: Preimplantational Genetic Test for Structural Reorganizations. This test helps detect chromosomal rearrangements, such as translocations, that may affect the viability of the pregnancy or increase the risk of miscarriage. It is performed by analyzing cells obtained from the trophectoderm by embryo biopsy.

Prenatal genetics

Specialists perform various genetics studies during pregnancy. Some of these are preventive, while others are required in cases with a suspected high risk for genetic or chromosomal conditions in the fetus. In addition, specialists indicate additional testing when there’s vulnerability to possible fetal abnormalities during gestation.

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FETAL DNA MATERNAL BLOOD TEST (NIPT)
The Maternal Blood Fetal DNA Test, or NIPT (Non-Invasive Prenatal Testing), is a non-invasive genetic study performed as early as the ninth or tenth week of gestation. This test involves the collection of a blood sample from the mother, and its objective is to detect the presence or absence of specific chromosomal abnormalities in the fetus. Specialists perform the NIPT in addition to other routine pregnancy tests and controls. It is important to emphasize that it’s a screening study and should not be considered a deﬁnitive diagnosis.

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CHORIONIC VILLUS SAMPLING AND AMNIOCENTESIS
These are invasive diagnostic genetic studies performed by chorionic villus sampling (CVS) or amniocentesis (amniocentesis). Ideally, these procedures are reserved for situations with a clear indication, such as presenting a very high risk of trisomies identiﬁed through Biochemical and Ultrasound Genetic Screening, performed between 11 and 13.6 weeks of gestation. They are also justified in the presence of fetal structural or morphological anomalies detected during ultrasound or when the fetal DNA test shows positive results.