This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
Prenatal genetic tests such as amniocentesis (drawing some amniotic fluid from around a 16-week fetus) always carries a small risk of miscarriage. Now, a partnership between a group of Chinese researchers and a San Diego biotech company may result in a simple no-risk blood test that detects defects caused by single-gene mutations.
Chinese University of Hong Kong scientists report in the Proceedings of the National Academy of Sciences that they devised a technique that locates a fetus's DNA molecules in blood samples taken from its mother. The fetal DNA or genetic material, which tends to be shorter than that of the mom, is duplicated and subjected to a “molecular counting” technique that tallies both mutant and normal genetic material. The new method overcomes what had been the major obstacle to such testing: distinguishing fetal DNA inherited from mom from mom's own DNA,
The range of single-gene disorders is vast, from cystic fibrosis to sickle-cell anemia (a disease in which abnormal amounts of iron-rich protein or hemoglobin cause normally round red blood cells to be sickle- or c-shaped and to clump together, blocking blood flow to limbs and organs). Biotech company Sequenom, which is already developing a blood test for Down’s Syndrome, says it plans to begin work on a commercial test for single-gene disorders.
“If you look at the very rare disorders, you’re into the five to ten- thousand range,” of diseases that might be detected with this test, says Harry Stylli, president and chief executive of the California-based company, which licensed the technology from the university. He notes that, eventually, it may be possible for physicians to order a customized battery of tests based on a patient’s risk profile.
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