PGD and PGS technologies benefit infertile couples Dr. Lei Caixia, a geneticist, introduced to us that PGD and PGS are both third generation IVF technologies. PGD refers to pre-implantation genetic diagnosis for couples with chromosomal abnormalities and genetic diseases, while PGS refers to pre-implantation aneuploidy screening for couples with a high risk of aneuploidy such as recurrent miscarriage, recurrent implantation failure, and severe oligospermia. Currently, PGD and PGS can be performed by PCR, FISH (fluorescence in situ hybridization), gene chip, second-generation sequencing and other technologies, and each center can choose the appropriate strategy for the technical operation. The single nucleotide polymorphic gene chip used in the Chi-Chi Center has higher resolution than the comparative genomic hybridization gene chips currently used in most international centers, and the single nucleotide polymorphic gene chip can achieve genome-wide haplotype analysis of single nucleotide polymorphic loci, which has great potential for application in preimplantation single gene genetic disease diagnosis, in addition to diagnosing chromosomal diseases. Before the introduction of gene chip technology, PGD of chromosomal disorders was generally performed by FISH, which could only detect a limited number of chromosomes, and the diagnostic results obtained were very limited, and for couples with chromosomal abnormalities such as balanced translocations, the embryos would not only have unbalanced translocations, but also an increased risk of aneuploidy. For couples with chromosomal abnormalities such as balanced translocations, the risk of aneuploidy is also elevated, and therefore the FISH technique may miss the diagnosis. Gene microarray solves this problem well, enabling screening of all chromosomes and meeting clinical needs. PGD for most monogenic diseases is achieved by PCR technology, which requires individualized testing protocols designed for each monogenic disease, which is time-consuming and labor-intensive. With the introduction of single nucleotide polymorphic microarray technology, couples with a clear genetic disease gene can apply single nucleotide polymorphic gene microarray technology to achieve preimplantation diagnosis of that single gene disease as long as the diagnosis of that disease is clear and there is already a close relative with the disease in the family, and aneuploidy screening is performed at the same time, avoiding the birth of children with chromosomal diseases while avoiding the birth of children with genetic diseases . The third generation of IVF technology is a primary prevention The definitive diagnosis also requires amniocentesis The main purpose of the third generation of IVF technology is to avoid the birth of children with genetic disorders, while reducing the risk of miscarriage, which is a primary prevention measure. “The standard process of third generation IVF also includes amniocentesis in the middle of pregnancy for a definitive diagnosis. The standard procedure for third-generation IVF also includes amniocentesis in mid-pregnancy for a final and definitive diagnosis to avoid the birth of defective children due to the limitations of the third-generation IVF technology itself”. Dr. Lei Caixia said. After years of operation, the center has developed a complete set of procedures from ovulation promotion, to embryo in vitro culture and genetic testing, to post-transfer obstetric examination and diagnosis. We not only have a team of excellent assisted reproduction clinical experts led by Professor Sun Xiaoxi, but also a first-class embryo culture laboratory and genetic diagnosis laboratory, thus guaranteeing the implementation of PGD and PGS technologies in terms of hardware and software. At present, most of the third-generation IVF techniques in Ji’ai use day 5 blastocyst testing followed by transfer, and the clinical pregnancy rate has been stable at over 60%, and the success rate of PGD/PGS diagnosis has been maintained at 95%, both of which measure the clinical and laboratory levels to international standards. “At the same time, we have established a follow-up mechanism to ensure the follow-up service of third-generation IVF. Usually, we perform peripheral blood HCG test 14 days after transplantation to determine whether biochemical pregnancy is reached, and if biochemical pregnancy is reached, we have to establish a follow-up mechanism. Generally, 1 month after biochemical pregnancy is determined, we have to determine whether clinical pregnancy is reached by ultrasound examination, after which, amniocentesis is performed around 18 weeks of pregnancy. In addition, a long-term post-birth follow-up mechanism has been established for third-generation IVF, and the hospital has The hospital has a dedicated team to carry out follow-up visits and improve the collection and summarization of medical history.” Dr. Lei Caixia said. In addition, amniocentesis is another major advantage of the center. The genetic department is also an important part of the Prenatal Diagnostic Center of the Red House Hospital, and has long undertaken the task of prenatal genetic diagnosis in the center. The amniocentesis procedure can be scheduled in the afternoon, and the waiting time for the procedure is less than one day. In addition, the center is currently implementing the simultaneous diagnosis of gene chip and amniotic fluid karyotype, and the diagnosis of chromosomal micro-repeats and micro-deletions, which has improved the diagnosis rate, reduced the rate of misdiagnosis and leakage, and also accelerated the diagnosis speed. As a result, it does not require a long appointment time to visit the center, and the report is notified by phone within 2 weeks and delivered by courier at the same time, which is greatly convenient for patients. More than three hundred cases of three-generation IVF have been completed Zhang Yueping, director of the center’s genetic unit, introduced that since 2013, gene chip technology has been routinely applied to the clinic, basically replacing the traditional FISH technology. In terms of application, the center has completed more than three hundred third-generation IVF cases, most of which are couples with chromosomal abnormalities or carrying genetic disease-causing genes, requiring embryonic chromosomal or genetic diagnosis (PGD), and a few are couples with unexplained recurrent spontaneous miscarriages and repeated IVF implantation failures, expecting to improve the implantation rate and reduce the miscarriage rate through embryo aneuploidy screening (PGS As the clinical role of PGS is controversial internationally, Gathering is very strict in controlling the indications for PGS, firstly, a qualified genetic counselor will take a detailed medical history and include the patient, and then it will be reviewed by the ethics committee to avoid abuse of the technology. Because genetics and assisted reproduction are inextricably linked, the center is divided into two major parts: assisted reproduction and genetics. The main work undertaken by the genetic department includes clinical genetic counseling, prenatal diagnostic procedures (amniocentesis and chorionic villus sampling), cytogenetic diagnosis, diagnosis of some monogenic genetic diseases and pre-implantation diagnosis. At present, all genetic testing involved in the center’s clinical practice is done by itself, and the laboratory team consists of three clinical geneticists and nine laboratory technicians, all of whom have undergone rigorous training in related technologies at home and abroad.