(UPDATED: See below.)Many infertile couples undergoing in-vitro fertilization rely on genetic screening of their fertilized embryos to improve their chances of delivering a healthy baby. But that technique, known as preimplantation genetic screening, has recently taken some hits on the scientific level, with one recent study finding that it not only fails to improve fertility rates, but may actually worsen the odds for older women. (See this WSJ story for details.)
For one thing, the procedure itself, in which a single cell is removed from a three-day-old embryo for testing, may actually damage the embryo. Other problems may result if the DNA from that cell can’t be fully “amplified” (that is, duplicated a number of times) in order to yield enough genetic material for testing. And some scientists question whether testing for abnormal numbers of chromosomes — a condition known as aneuploidy — really yields benefits for anyone but women who have suffered multiple miscarriages.
In any event, there seems little doubt that many couples would welcome any development that improves the accuracy and efficacy of preimplanation screening. Which, it turns out, is exactly what Gene Security Network, a Portola Valley, Calif., biotech, hopes to offer soon — even though it only appears to address some of those concerns.
GSN says it has developed a technique that allows for highly accurate testing for both aneuploidy and a number of genetic diseases such as muscular dystrophy and cystic fibrosis using DNA from a single cell. The company hasn’t explained its technology in detail, but says it relies on “advanced informatics” and existing gene maps such as that developed by the Human Genome Project to “reconstruct” embryonic DNA with high accuracy.
Following a brief conversation with Ted Driscoll, a VC at GSN backer Claremont Creek Ventures, I have a better — although still far from complete — understanding of what the company is up to. Essentially, GSN starts with genetic samples from both parents, which it can scan for the individual single-letter DNA variations associated with particular genetic diseases. Using that background information, the company can make highly educated guesses about which stretch of DNA in the embryo came from which parent, allowing GSN to “reconstruct” DNA that goes missing in the course of single-cell analysis. In turn, that makes it possible to figure out, for instance, whether the embryo has inherited two copies of a dangerous gene that could cause a disease like cystic fibrosis.
GSN says its technology will begin rolling out in IVF clinics next year. The company just raised $4M in a first funding round, which it says will allow it to commercialize its techniques. Investors in the round include Claremont Creek Ventures, Sequoia Capital, the Huntington Reproductive Center, and Marissa Mayer, a Google vice president in charge of Google Health and other search products.
UPDATED: Expanded the description of GSN’s technology based upon further reporting.