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First Birth Reported for Full-Genome Screened IVF Embryo

Pregnancy health (CDC)

(U.S. Centers for Disease Control)

A British woman gave birth to a boy in June, following a full genomic sequencing of the embryo to identify potential genetic disorders. Researchers at University of Oxford in the U.K., with colleagues from the reproductive genetics company Reprogenetics in New Jersey and fertility centers in the U.S., described their results today in London at a meeting of the European Society of Human Reproduction and Embryology.

The team led by Oxford genetics professor Dagan Wells applied the technique full genome sequencing, often called next generation sequencing, of DNA that analyzes and catalogs genetic sequences — the precise order of genetic molecules — in an individual genome, and compares those sequences to other genomes. The technique produces vast amounts of data, requiring powerful and sophisticated systems.

Wells says this study was the first time individual embryos were analyzed with full genomic sequencing, making it possible to identify genetic disorders, abnormal chromosomes, and mutations, providing “an unprecedented insight into the biology of embryos.” With in-vitro fertilization (IVF) today, only about 30 percent of embryos selected for transfer complete implantation, and genetic or chromosomal defects are suspected as reasons for the low rate of success. Genetic screening of embryos has been tried, say the researchers, but clinical trials uncovered drawbacks and less than optimal performance.

In their study, the team analyzed the genomes of cells with known defects and mutations, including the inherited disorder cystic fibrosis. In the next step, the researchers analyzed 45 embryos, which had tested with other techniques for abnormalities, using full-genome sequencing. The results were evaluated independently, which accurately identified and matched the defects and abnormalities in both samples, including all 10 cells carrying the cystic fibrosis mutation.

Wells and colleagues then tried the technique with two IVF clinic patients, age 35 and 39, with a history of miscarriage. The full genomic sequencing of blastocysts — five day-old embryos — from the two women identified two or three blastocysts with healthy chromosomes in each patient. The screening returned results in about 16 hours, removing the need to freeze the embryos while waiting for the results.

A single healthy embryo from those identified in the tests were implanted in each of the patients, both of whom reported normal pregnancies. The first pregnancy resulted in the birth in June of a healthy baby boy.

Wells believes applying full genomic sequencing to IVF services can improve the identification of healthy embryos and improve the clinics’ success rates, and reduce the risks of miscarriage. A randomized clinical trial of the technique is planned for later this year.

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