Embryo testing stokes designer baby concerns
Screening pioneer considering opening labs in Toronto, Montreal
By Sharon Kirkey, Postmedia News September 19, 2011
The era of designer babies may be closer than most people think, one of Canada's leading figures in reproductive medicine is warning.
New techniques that test each and every chromosome in human embryos for abnormalities, and screen for hundreds of genetic diseases, are opening the door to a new era in assisted procreation - one that Canadians have not even begun to grapple with, says Dr. Roger Pierson, director of the Reproductive Biology Research Unit at the University of Saskatchewan.
"We desperately need a national think-tank on how we're going to accept or reject or implement the changes that are coming," Pierson says.
Instead, we're still focusing on problems as old as the technology itself, he says. "We're still worrying about, 'Do we disclose the identity of sperm donors?'" Pierson says. "We haven't caught up with the old yet, let alone have the foresight to go into this coming world with the depth that we need to."
His message comes as a world pioneer in embryo screening is looking to move into the Canadian market.
Dr. Santiago Munné - developer of the first pre-implantation genetic test to detect Down syndrome and other chromosomal abnormalities - is considering opening embryo-screening labs in Toronto and Montreal.
Munné, founder and director of Reprogenetics, a New Jersey-based company that has screened more than 24,000 embryos, including embryos created in Canadian fertility clinics, since its inception in 2001, believes Montreal is a prime market for expansion. Quebec is now pay-ing for up to three invitro fertilization treatment cycles for infertile couples - with the proviso that just one embryo be transferred at a time in most cases. In Ontario, an expert panel has recommended the province fund up to three cycles of IVF, and patient groups are pushing other provinces to do the same.
"If you have the rule that you can only have one embryo transferred then PGD becomes more necessary because you really need to know which to transfer," says Munné, who will be a featured speaker next week when Canada's fertility doctors gather for the annual meeting of the Canadian Fertility and Andrology Society - a meeting that is closed to the media.
Pre-natal genetic diagnosis is designed to select genetically "normal" embryos created through in vitro fertilization before they are transferred into a woman's uterus. Anomalies can be detected in embryos only two or three days old, based on a single cell.
The tests were original-ly developed for couples at high risk of transmitting devastating hereditary diseases to their children - diseases such as myotonic dystrophy or Tay Sachs, a progressive neurodegenerative disease that attacks nerve cells and usually kills children before their fifth birthday.
Unlike older prenatal testing, such as amniocentesis, embryo screening prevents couples from having to discover three months or longer into a pregnancy that the fetus is "affected", and then face the anguish of deciding whether to terminate the pregnancy.
With pre-implantation genetic testing, the diagnosis is made before the woman ever becomes pregnant.
Only limited embryo screening is now being performed in Canada. Most Canadian fertility clinics send biopsies from embryos to U.S. centres for testing.
The risk of damage to the embryo is low, about one to two per cent. There's also a one-to two-per-cent error rate, meaning the tests miss a defect or wrongly declare a healthy embryo abnormal.
Munné says screening at his lab costs about $2,500.
The technology benefits couples that suffer from recurrent pregnancy loss, meaning one miscarriage after another, Munné says. "These couples produce a lot of chromosomally abnormal embryos." The technology can also be combined with the screening of any gene disorder known in the couple. "If we know the mutation," Mun-né says, "we can screen for it."
But virtually every disease of adulthood has an embryonic or fetal origin, scientists are discovering - raising the prospect of one day being able to screen embryos for early heart attack, or early-onset Alzheimer's disease, Pierson says.
In the future we may also be able to select for "more refined traits," he says, such as musical ability or mathematic skills. Moreover, as scientists decipher the genome, learning what different genes do, how they interact, and how to change them, "then we start getting into much more delicate territory," Pierson says. "The territory is, you design what you want."
Munné rejects fears that the technology could lead to designer babies. "I don't have any problem with perfect babies," he said.
But 70 per cent of embryos are chromosomally abnormal, he said. Looking for one specific gene for a "desirable trait" would reduce the odds to one in 13 embryos, when the average couple undergoing IVF produces only eight, he said.