Friday, August 18, 2017

Embryo Selection in China (Nature)


China’s embrace of embryo selection raises thorny questions   
Nature vol 548, pp272–274 (2017)

Fertility centres are making a massive push to increase preimplantation genetic diagnosis in a bid to eradicate certain diseases.

... Early experiments are beginning to show how genome-editing technologies such as CRISPR might one day fix disease-causing mutations before embryos are implanted. But refining the techniques and getting regulatory approval will take years. PGD has already helped thousands of couples. And whereas the expansion of PGD around the world has generally been slow, in China, it is starting to explode.

... Genetic screening during pregnancy for chromosomal abnormalities linked to maternal age has taken off throughout the country, and many see this as a precursor to wider adoption of PGD.

Although Chinese fertility doctors were late to the game in adopting the procedure, they have been pursuing a more aggressive, comprehensive and systematic path towards its use there than anywhere else. The country’s central government, known for its long-term thinking, has over the past decade stepped up efforts to bring high-quality health care to the people, and its current 5-year plan has made reproductive medicine, including PGD, a priority ...

Comprehensive figures are difficult to come by, but estimates from leading PGD providers show that China’s use of the technique already outpaces that in the United States, and it is growing up to five times faster.

... there are concerns about the push to select for non-disease-related traits, such as intelligence or athletic ability. The ever-present spectre of eugenics lurks in the shadows. But in China, although these concerns are considered, most thoughts are focused on the benefits of the procedures.

... And the centres with licences to do PGD have created a buzz in their race to claim firsts with the technology. In 2015, CITIC-Xiangya boasted China’s first “cancer-free baby”. The boy’s parents had terminated a prior pregnancy after genetic testing showed the presence of retinoblastoma, a cancer that forms in the eyes during early development and often leads to blindness. In their next try, the couple used PGD to ensure that the gene variant that causes retinoblastoma wasn’t present. Other groups have helped couples to avoid passing on a slew of conditions: short-rib-polydactyly syndrome, Brittle-bone disease, Huntington’s disease, polycystic kidney disease and deafness, among others. ...

Joe Leigh Simpson, a medical geneticist at Florida International University in Miami, and former president of the Preimplantation Genetic Diagnosis International Society, is impressed by the quality and size of the Chinese fertility clinics. They “are superb and have gigantic units. They came out of nowhere in just 2 or 3 years,” he says. ...

People in China seem more likely to feel an obligation to bear the healthiest child possible than to protect an embryo. The Chinese appetite for using genetic technology to ensure healthy births can be seen in the rapid rise of pregnancy testing for Down’s syndrome and other chromosomal abnormalities. Since Shenzhen-based BGI introduced a test for Down’s syndrome in 2013, it has sold more than 2 million kits; half of those sales were in the past year.

... The Chinese word for eugenics, yousheng, is used explicitly as a positive in almost all conversations about PGD. Yousheng is about giving birth to children of better quality. Not smoking during pregnancy is also part of yousheng. ...
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