HEALTH - Less Evasive DNA Test for Fetuses

"DNA Blueprint for Fetus Built Using Tests of Parents" by ANDREW POLLACK, New York Times 6/6/2012

Excerpt

For the first time, researchers have determined virtually the entire genome of a fetus using only a blood sample from the pregnant woman and a saliva specimen from the father.

The accomplishment heralds an era in which parents might find it easier to know the complete DNA blueprint of a child months before it is born.

That would allow thousands of genetic diseases to be detected prenatally. But the ability to know so much about an unborn child is likely to raise serious ethical considerations as well. It could increase abortions for reasons that have little to do with medical issues and more to do with parental preferences for traits in children.

“It’s an extraordinary piece of technology, really quite remarkable,” said Peter Benn, professor of genetics and developmental biology at the University of Connecticut, who was not involved in the work. “What I see in this paper is a glance into the future.”

The paper, published Wednesday in the journal Science Translational Medicine, was written by genome scientists at the University of Washington. They took advantage of new high-speed DNA sequencing and some statistical and computational acrobatics to deduce the DNA sequence of the fetus with about 98 percent accuracy.

The process is not practical, affordable or accurate enough for use now, experts said. The University of Washington researchers estimated that it would cost $20,000 to $50,000 to do one fetal genome today.

But the cost of DNA sequencing is falling at a blistering pace, and accuracy is improving as well. The researchers estimated that the procedure could be widely available in three to five years. Others said it would take somewhat longer.

It is already possible to determine the DNA sequence of a fetus by acquiring fetal cells through amniocentesis or chorionic villus sampling, which involves testing the placental tissue. But these procedures are invasive and carry a slight risk of inducing a miscarriage.

For couples worried about passing on a genetic disease, it is also possible to use in vitro fertilization and have an embryo genetically tested before implantation into the womb.

But the technique described in the paper would not require complete cells from the fetus and would make such DNA testing easier and less risky.