Designer babies

DNA testing on embryos can provide hopeful parents with the answers they need, but is it right?
By Tamlyn Vincent

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Imagine being able to give children a life free from the worry of genetic disease by eliminating genetic abnormalities from the very start. With the development of genetic testing on embryos, these possibilities are a reality.
 
Preimplantation genetic testing (PGT) is being done more frequently with in vitro fertilisation (IVF), to test embryos’ DNA before putting them back in the womb. Dr Lawrence Gobetz, an infertility specialist in Joburg, explains that there are two reasons to biopsy embryos. The first is to perform preimplantation genetic screening (PGS), where the number of chromosomes is checked. If there aren’t 24 chromosomes, the embryo is at risk of Down’s syndrome or other chromosomal abnormalities. PGS can improve the success rates of pregnancy, says Jaysen Knezovich, laboratory director at Genesis Genetics. “Embryos that are genetically normal are more compatible with life,” says Knezovich, so failure rates are reduced. But Gobetz cautions that it’s possible to find no normal embryos, especially with older couples, thereby excluding them from IVF.
 
Preimplantation genetic diagnosis (PGD), the other reason to biopsy embryos, is done to exclude genetic diseases such as Tay Sachs or cystic fibrosis, that one or both parents have or carry, says Gobetz. A specific test is designed around the genetic profiles of the parents, to identify a genetic condition in an embryo in order to eliminate it.
 
Family value
 
While PGD can help to exclude genetic diseases, it can’t tell how many chromosomes an embryo has. So Gobetz says it makes sense for couples doing PGD to also do PGS, but this is costly. PGS currently costs around R22 000, while PGD can cost R35 000 for one test.
 
For many couples, going through fertility treatments is a difficult experience. Taryn, a mom in Cape Town, found her treatments stressful and invasive, especially when she and her husband didn’t know what the problem was. “PGT provides insight into the possible reason for pregnancy failures,” says Knezovich, which is valuable for the doctor and patient, especially if it means preventing the trauma of more pregnancy losses. Taryn points out that treatments are expensive anyway, so she would rather pay more for these tests and have answers. And couples that discover IVF isn’t a viable option will at least have that answer.
 
Going forward
 
For some people, the issue isn’t the cost but the ethics. There are religious arguments and others claiming potential misuse. Thanks to advances in DNA profiling it could soon be possible to get all sorts of genetic information from an embryo, giving rise to concerns about creating designer babies. According to Knezovich the debates are mostly unresolved. In the meantime, genetic testing is helping to build healthy families, although there are legal regulations. An embryo’s sex can be determined, for example, but performing gender selection without a sound medical reason is illegal in South Africa.
 
Genetic testing still has a long way to go, with new methods only in experimental phases. And even when they do become available they are likely to be very expensive. For now, Gobetz hopes that PGT will become more cost effective in the next few years, giving more couples the chance to have a healthy child.

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