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Wednesday, November 13, 2024

Genetic Screening Now Lets Parents Pick the Healthiest Embryos

At 18 months old, Aurea Yenmai Smigrodzki is inquisitive like any other toddler. She likes peanut butter, the beach, and mobile phones—or any toys that look like phones. She likes to copy her mum and dad, Thuy and Rafal, when they are using theirs. Aurea doesn’t know it yet, but her birth was very special: She is the world’s first PGT-P baby, meaning she is statistically less likely than the rest of us to develop a genetic disease or disorder throughout her life.

PGT-P stands for preimplantation genetic testing for polygenic disorders. It is conducted in conjunction with IVF and allows prospective parents to actively select which of their own embryos to take, based on the strength of its genes. Rafal and Thuy were given the genetic profiles of five prospective embryos, and Aurea’s was the strongest candidate, because her embryo had the fewest recognizable genetic mutations that could go on to cause disease. “It was really a no-brainer,” says Rafal of the choice he and Thuy made to undergo the genetic screening process. “If you can do something good for your child, you want to do it, right? That’s why people take prenatal vitamins.”

All parents want their children to be healthy, but lots have reason to fear passing on something harmful. Our genes can predispose us to developing all kinds of diseases: diabetes, heart disease, cancers, and many more. With this in mind, one could be forgiven for assuming that Rafal or Thuy carried some inheritable condition and wanted to break the chain. But the reality, Rafal admits, is that he “simply knew that PGT-P existed,” and so he decided to give it a try.

Rafal is a neurologist and has an interest in pioneering technologies, referring to himself as a “techno-optimist.” He has even signed up to have his brain cryogenically stored when he dies, in the belief it will one day be resurrected, thoughts and spirit intact. In his eyes, genetic screening of embryos is nothing crazy or even special, it is simply the natural next step for humans to take. “It’s like the first time someone ever made a phone call—sure, it was a unique moment, but really it was just the beginning of something that now everybody does,” Rafal muses. “In 10 years’ time, this kind of polygenic testing will be completely non-controversial. People will be doing it as a matter of course.”

Thuy and Rafal screened their embryos through Genomic Prediction, the first of a couple of biotech firms in the US to open up genetic screening services to prospective parents. Taking DNA samples from the embryo cells alongside genetic sequences from both parents, analysts are able to draw up a set of markers from which they can construct a full genetic picture of the embryo. This effectively fast-forwards its development process to create a projection of what level of health a child born with those genes might enjoy. To help their clients put this data into context, each embryo is given a health score based on the existing mutations in its genes which could potentially one day be life limiting, and the would-be parents are shown how that score compares against the population average. The ranking takes into account the severity of conditions, if shown, as well as the ethnicity of the embryo, since this can also have an impact on disease incidence.

Aurea is the product of that ranking: she was the top-rated embryo out of Thuy and Rafal’s IVF collection and the cells they chose to give the best possible chance at living a long, disease-free life. When Aurea is older, she will have access to the full set of embryonic screening data shared with her parents. She will probably have her own genome sequenced, too—Rafal has already purchased a home testing kit for her—and use that information to guide her approach to health and lifestyle through her life. “I hope she will be glad for it,” says Rafal.

“People ask me if I’m trying to play God in choosing to do this,” Rafal adds, anticipating the next big question. He believes that “genetic selection is not playing God, it’s working as a mechanic on molecular machines that sometimes break and need to be fixed.” Of course, good genes are by no means a guarantee for a long and healthy life, and carrying an abnormality or even living with a hereditary disease does not always equate to a poorer quality of life. Rafal does not for a moment believe that passing on unhealthy genes makes someone a bad parent, either. But he is unequivocal in his belief that he has done the best thing for his child by giving her the best odds against genetic disease. “As parents, we act as the health champions of our children, and it makes sense to treat genes not as mysterious determinants of identity, but something that you know is there and is important; these are the same principles I apply in trying to take good care of my own health. What matters,” he continues, “is that the process was successful, my child was born healthy, and she is happy.”

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