Embryonic biology testing

Preimplantation Genetic Testing (PGT), also known as Embryo Genetic Screening, is a method of screening embryos for genetic abnormalities during the in vitro fertilization (IVF) cycle. It can help select healthy embryos for transplantation, increasing the chances of successful pregnancy and giving birth to healthy babies. The following is a detailed explanation of embryonic biology testing:

1. Principle: Embryonic biology testing is usually carried out when the embryo develops to 6-8 cell stages. It involves sampling one or more cells of an embryo and analyzing the genetic information of the sampled cells. The commonly used PGT techniques currently include PGT-A (embryo chromosome screening), PGT-M (embryo monogenic disease detection), and PGT-SR (structural staining weight screening).

2. PGT-A: PGT-A is used to detect chromosomal abnormalities in embryos, such as whether the embryo carries additional chromosomes (trisomy) or missing chromosomes (monosomy). Its main purpose is to reduce the transfer of embryos with chromosomal abnormalities, in order to improve the success rate of pregnancy and reduce the risk of miscarriage.

3. PGT-M: PGT-M is used to detect whether embryos carry specific single gene disease mutations. This test is suitable for couples carrying genetic disease mutations to avoid passing on the disease to their offspring. PGT-M needs to be detected at predetermined mutation sites and select embryos that do not carry mutations for transplantation.

4. PGT-SR: PGT-SR is used to screen embryos for carrying structural chromosomal rearrangements. Structural chromosome rearrangement refers to the partial deletion, duplication, or rearrangement of chromosomes. PGT-SR can help screen embryos carrying structural chromosomal rearrangements to reduce the transfer of abnormal embryos.

5. Sampling method: PGT embryo sampling is usually carried out through embryo biopsy or embryo cell population sampling. Embryo biopsy uses subtle attraction or laser to extract one or more cells for genetic analysis. The sampling of embryonic cell populations involves genetic analysis of a portion of the sampled cells.

6. Ethical and legal issues: Due to the involvement of PGT in screening and selection of embryos, there are some ethical and legal issues, such as selective screening and selection of human embryos. Therefore, the use and restrictions of PGT vary in different countries and regions. Before conducting PGT, it is recommended to consult a doctor and genetic counselor to understand local regulations and ethical guidelines.

It should be noted that embryonic biology testing is not 100% accurate, and there is still a certain misdiagnosis rate. In addition, embryonic biology testing cannot guarantee successful pregnancy or the birth of a healthy baby. Therefore, before conducting PGT, it is recommended to consult and discuss in detail with doctors and genetic counselors to understand its applicability, advantages, limitations, and risks.