Zahra Sadat Aghaei Shahri,1,*
1. Zahra Sadat Aghaei Shahri Member of the Research Committee of the Islamic Azad University of Mashhad. Iran
Introduction: Preimplantation Genetic Diagnosis (PGD) Cytogenetic analysis is performed to determine the presence or absence of genetic disease in the zygote before implantation. In vitro fertilization is an assisted reproductive technique. Chromosomal abnormalities are disorders of the number or structure of chromosomes. Genetic diseases Diseases caused by genetic mutations that may be inherited from the parents' genome or created in the womb.
Methods: Articles reviewed in databases published in 2002-2021 . Search by keywords Chromosomal abnormality, Preimplantation genetic diagnosis (PGD), Single gene disorder, In vitro fertilization .Eight articles from the google scholar database and 11 articles from the pubmed database were selected. 5 articles from the google scholar database and 5 articles from the pubmed database were removed due to non-compliance, and finally 9 articles were reviewed.
Results: in 1 article states that PGD was introduced in the early 1990s.
in 9 article states that PGD is used to prevent the transmission of defective genes to the fetus and termination of pregnancy in couples who have chromosomal inherited disorders or a family history or have a child with a genetic disorder.
In 3 articles, it is stated that in PGD, single-gene abnormalities, hereditary chromosomal abnormalities and X-related abnormalities are detected in the fetus before entering the uterus, and with consent and by considering the usual criteria in an appropriate time frame, prevention of Continuation of pregnancy is done.
Based on 7 studies, In PGD, 18-16 hours after fertilization, the ovums are evaluated for fertilization and those that have suitable characteristics are cultured. Then, on the third day, when the embryo is in the 6- to 8-cell stage, one or two blastomeres are isolated and the cell's DNA is amplified. They are evaluated for genetic diseases, and if they are healthy, the embryo is transferred to the mother's uterus. But in case of infection, the transfer does not take place. In this method, instead of trying to get pregnant several times, more embryos are formed during an IVF period and the embryos are genetically examined. They are more likely to have a healthy fetus. Termination of pregnancy and recurrent miscarriage no longer occur.
In one study, the use of PGD to diagnose the risk of late-onset diseases and cancer-prone genes was also discussed.
An article on the disadvantages of PGD states that there are a number of misdiagnosis cases and they are very expensive.
Conclusion: People with special hereditary conditions should be under the care of an embryologist, gynecologist and geneticist and with careful counseling and awareness of the limitations and costs, they can use the PGD method to prevent the transmission of defective genes to their offspring and reduce the risk of miscarriage.
Keywords: Chromosomal abnormality, Preimplantation genetic diagnosis (PGD), Single gene disorder, In vitro fer