In 1998, the US-based Genetics and IVF (GIVF) Institute partnered with Fudan University Obstetrics and Gynecology Hospital to create Shanghai Ji Ai Genetics and IVF Institute China-USA Center, the first IVF and prenatal genetics center in China. The institute was established to offer the latest infertility treatment technologies developed for infertility treatment and advance China’s progress in reproductive medicine. Shanghai Ji Ai was the first clinic in Eastern China to perform intracytoplasmic sperm injection (ICSI), the first to achieve a live birth from a frozen egg in Shanghai, and the first approved by the Shanghai Health Authority to provide preimplantation genetic diagnosis (PGD) services. Over the past 18 years, Shanghai Ji Ai has helped patients from 34 countries achieve more than 17,000 successful births.
In January 2016, Shanghai Ji Ai realized another milestone. It became the first institute in China to see the birth of a baby conceived using karyomapping and IVF. Karyomapping is an advanced PGD technique that assesses an embryo for a specific monogenic condition before transfer into the uterus. The goal is to prevent couples with a known risk of transmitting an inherited genetic disorder of having children affected with that disorder.
iCommunity spoke with three of the scientists at the Shanghai Ji Ai Genetics and IVF Institute involved with this historic event, Professor Sun Xiao-xi, Vice President; Lei Cai-xia. Associate Chief Physician; and Sun Hai-yan, Clinical Laboratory Examiner.
Q: What is the status of rare genetic diseases research in China?
Sun Xiao-xi (SX): In the past, research was scattered among various hospitals. Recently, the government has started paying more attention to rare diseases research. Under government guidance, rare diseases research centers have appeared and hospitals have strengthened their cooperation with each other. For example, Children’s Hospital and the Obstetrics and Gynecology Hospital of Fudan University now collaborate in studies focusing on rare monogenic disorders. Families that have children afflicted with rare diseases will be involved with prepregnancy screening, prenatal diagnosis, and follow-up after birth.
The recognition and support of rare diseases research in China is getting better and better. On the eve of International Rare Disease Day, the Shanghai Health and Family Planning Commission issued guidelines for screening, diagnosis, treatment, rehabilitation, research, and related policy development of rare diseases. For the first time, a series of activities were planned in Shanghai to acknowledge International Rare Disease Day. The National Natural Science Fund is providing more financial support for rare diseases research in China.
Q: What methods do you use to study monogenic conditions?
SX: Currently, next-generation sequencing (NGS) and Sanger sequencing are widely used to analyze monogenic conditions. We use NGS to determine the sequence of pathogenic or suspected pathogenic genes and integrate that with available gene information from existing databases or literature to develop a feasible and reliable detection panel of monogenic diseases. Then, we compare sequence data for a test sample and use the resulting data to make a disease prediction. We use multiple NGS platforms, including the Illumina MiSeq and NextSeq Systems.
“Karyomapping is based on genome-wide linkage analysis... Each test doesn’t need individual design, greatly shortening detection time, cost, and labor.”
Lei Cai-xia (LC): For embryo PGD, we mainly used Sanger sequencing and arrays. Recently, we started using the Illumina iScan System and karyomapping to assess the risk of an embryo carrying a monogenic condition before transfer into the uterus.
Q: Why did you choose to implement karyomapping?
SX: We have couples coming to us that already have a child afflicted with a rare disease. These families want to avoid passing on that disorder to future children. Karyomapping can help by detecting monogenic diseases in embryos before implantation. With other methods, we have to wait until the second trimester of pregnancy to make a diagnosis. This earlier detection means that family planning decisions can be made earlier in the pregnancy.
Q: What advantage does karyomapping have over other methods?
LC: The current method for identifying single-gene diseases is mutation diagnosis and haplotype analysis. This process requires a specific cycle for each gene, making it long and expensive. Karyomapping is based on genome-wide linkage analysis. Using approximately 300,000 single nucleotide polymorphisms (SNPs) located across the entire genome, karyomapping can be applied to multiple monogenic diseases simultaneously, greatly shortening detection time, cost, and labor.
Q: How is PGD with karyomapping performed?
Sun Hai-yan (SH): We begin with a pedigree analysis. We compare DNA information from the embryos with DNA from the parents and the proband (an affected individual in the family) to paint a family genealogy. Next, we start the PGD process. After ovulation, ICSI fertilization, and blastocyst culture, our embryologist biopsies 3-5 cells from the trophoblast using micromanipulation techniques. DNA from the biopsied cells undergoes whole-genome amplification in our genetic lab. The embryo DNA is then compared to the DNA of the parents and the proband to identify embryos that do not have the disease or chromosome aneuploidy.
Q: How was your experience using Bluefuse Multi Software?
SH: BlueFuse Multi Software is convenient to use. It integrates several databases, so that we can easily and accurately compare data from the embryo with reference information.
“For couples who are known carriers of monogenic diseases, PGD can help them give birth to unaffected offspring. PGD will have a profound impact.”
Q: Why was karyomapping suggested for the couple who recently gave birth to a baby conceived using PGD and IVF?
LC: Eight years ago, the couple gave birth to a daughter diagnosed with congenital adrenal hyperplasia (CAH), which is caused by a mutation in the CYP21A2 gene. After performing a gene detection study, it was determined that both parents were carriers of CAH. This means that any of their offspring would have a 1 in 4 chance of being afflicted with CAH.
Between 2012 and 2013, the couple had been pregnant twice. Amniocentesis results for both pregnancies showed that the fetuses had CAH. The couple came to Shanghai Ji Ai seeking help with having an unaffected child. After detailed counseling, the couple decided to undergo PGD using karyomapping.
Q: Can you describe the PGD and IVF procedures?
LC: After ovulation, ICSI fertilization, and blastocyst culture, the couple had four blastocysts available for genetic detection. We biopsied 3-5 cells from each trophoblast, isolated and whole-genome amplified DNA from the biopsied cells, and compared the embryo DNA to that of the couple and the proband, their 8-year–old daughter. Of the four embryos, we identified an embryo that was not positive for CAH and did not exhibit chromosome aneuploidy. The chosen blastocyst was transferred into the mother’s uterus and the pregnancy was successful. An amniocentesis was performed and the results were consistent with those from karyomapping. On January 29, 2016, the mother gave birth to an unaffected baby boy.
Q: What is the significance of the birth of this baby conceived through IVF with karyomapping in China?
SX: This birth symbolizes that PGD in China has risen to international standards.
Q: What do you think the impact of PGD will be in China?
SX: In China, we have such a large population that the actual incidence rate of rare diseases is fairly high. For couples who are known carriers of monogenic diseases, PGD can help them give birth to unaffected offspring. PGD will have a profound impact.
Karyomapping Assay. www.illumina.com/clinical/reproductive-genetic-health/preconception-fertility.html.
BlueFuse Multi Software. www.illumina.com/clinical/clinical_informatics/bluefuse.html.
iScan System. www.illumina.com/systems/array-scanners/iscan.html.
MiSeq System. www.illumina.com/systems/miseq.html.
NextSeq System. www.illumina.com/systems/nextseq-sequencer.html.