Preimplantation and prenatal testing performed at our hospital
Preimplantation genetic testing (PGT) is a method of analyzing the genetic information of fertilized eggs (embryos) generated by IVF to select embryos to be transferred and determine the order of transfer.
PGT is divided into three types depending on the purpose. PGT-M is performed to prevent serious genetic diseases caused by gene mutations. PGT-SR is performed for carriers of a chromosomal structural abnormality1 that may result in the birth of a child with a serious genetic disease and for recurrent miscarriage caused by a balanced chromosomal structural abnormality2. PGT-A is used to diagnose a chromosomal aneuploidy3 that cause implantation failure and recurrent miscarriage. Currently, this test is performed as a self-paid medical treatment, but it is possible that in the future it may develop into an insurance-covered medical treatment through advanced medical treatment.
Non-Invasive Prenatal genetic Testing (NIPT) is the maternal blood fetal chromosome test that determines whether there is a high or low probability that the fetus will have a high or low probability of having a number chromosome abnormality4 such as 21 trisomy (Down syndrome), 18 trisomy, or 13 trisomy by examining DNA fragments in the mother’s blood during pregnancy.
It is a highly accurate test with low physical burden on the patient. However, it is not the only test that can confirm the diagnosis, and genetic counseling before and after the test is essential because there are cases where concerns cannot be resolved. Our hospital has been conducting the test since 2013, and as a core facility in Tokushima Prefecture, we have a system in place where pregnant women can feel at ease in consultation in cooperation with specialists from the Genetic Counseling Department (Fig.).
Hereditary breast and ovarian cancer and surgery to reduce the risk
Hereditary breast and ovarian cancer (HBOC) is a congenital mutation in the BRCA1 or BRCA2 gene, and is reported to have a higher risk of developing breast cancer or ovarian cancer than the general population. Therefore, it is important to undergo surgery to remove the breast or ovaries to reduce the risk before breast cancer or ovarian cancer develops, or to undergo regular checkups to detect early cancer.
Risk-reducing salpingo-oophorectomy (RRSO) is performed to reduce the risk of developing ovarian and fallopian tube cancer in women with HBOC. Since April 2020, health insurance has been applied to RRSO for women diagnosed with HBOC who developed cancer. Until October 2023, 19 people have undergone the surgery at our department.
The surgery is performed through a small incision in the abdomen using a camera called a laparoscope, which is less invasive and allows for early recovery. RRSO prevents many cases of ovarian cancer. On the other hand, there is still a risk of peritoneal cancer, regular checkups are necessary even after surgery.
- a chromosomal structural abnormality: a state in which part of the chromosome structure has changed ↩︎
- a balanced chromosomal structural abnormality: a chromosomal structural abnormality that does not affect the amount of chromosomes ↩︎
- a chromosomal aneuploidy: a state in which the number of some chromosomes has changed due to a mutation ↩︎
- number chromosome abnormality: abnormalities caused by an increase in the number of chromosomes from two pairs to three or a decrease in the number of chromosomes from two pairs to one ↩︎