When Jamie Cassidy became pregnant for the first time, her fetus had a genetic mutation so severe that she and her husband, Brennan, decided to abort it in the second trimester. The next time they tried to have a baby, they weren’t going to take any chances. The plan was to use IVF and test the fetus’ DNA. They wanted to avoid implanting embryos with a single gene mutation that doomed the first pregnancy. And they began to think that it might be possible to save their future sons and daughters from other diseases.
The Cassidys’ doctor told them about Genomic Prediction, a company that can assess the likelihood that their children will develop diseases not linked to a single gene, such as heart disease, diabetes and schizophrenia. This test is not as invasive as screening for a single gene. All the company needed was an embryo biopsy. The science is still in its infancy, but the Cassidys didn’t mind. Brennan has type 1 diabetes and didn’t want to pass on the condition. “If I could predict that my baby would be less likely to have type 1 diabetes than I am, I would like to do that,” he told me. “I would spend all my money to find out.”
Thanks to more sophisticated genetic testing techniques, in vitro fertilization (an expensive, invasive treatment originally developed to help people with infertility issues) is becoming a tool for optimizing health. there is. A small number of companies offer screenings for a variety of diseases and disorders, from life-threatening (cancer) to life-altering (celiac disease). Genetic links to these symptoms are often: not very well understood or weak, is just one of many factors that determine whether a person will develop a particular condition. But bringing another human into space could be a scary enough prospect for some parents to turn to extensive genetic testing to select future offspring.
Genetic screening is an important part of IVF and pregnancy. decades. medical guidelines recommend Anyone who wants to become a mother should have the option of having their DNA tested to find out whether they are at risk of passing on dangerous genes, a practice known as carrier screening. be. If both parents have a particular mutation, your doctor will likely suggest in vitro fertilization and embryo screening. These measures have traditionally been limited to conditions associated with single gene mutations, such as Huntington’s disease, most of which are extremely rare and have a profound impact on a child’s quality of life. During IVF, embryos are also usually screened for chromosomal abnormalities to avoid miscarriages and non-genetic diseases such as Down syndrome.
As the scientific understanding of the genome advances, companies such as Genomic Prediction and competitor Orchid are offering tests that promise a more comprehensive look at a fetus’s genetic risks using so-called polygenic risk scores. It has started. The most common diseases are not linked to a single gene. Polygenic risk scores aim to predict the lifetime probability of diseases such as diabetes, where many genes contribute to a person’s risk. Consumer DNA testing companies such as 23andMe use these scores to estimate a customer’s likelihood of developing celiac disease, with the disclaimer that lifestyle and other factors can also influence that likelihood. Tell your customers if your is slightly above average. These risk scores could, in theory, help identify customers who need a colonoscopy early in life, for example.Or anyone who needs to double down on their New Year’s resolution to eat healthier. However, the current scientific consensus is that polygenic risk scores, even if obtained in practice, are still unable to provide useful insights into human health.
Analyzing fetal DNA to predict the likelihood of developing genetically complex diseases such as diabetes is an even trickier problem. The test can cost thousands of dollars, is usually not covered by insurance, and requires sending a small embryo sample to a company lab. In the United States, such tests do not require FDA approval. Genomic Prediction also provides customers with an assessment of which embryos are the “healthiest” overall. But the control these services offer is illusory, like promising to predict the weather a year in advance, said Robert Kritzman, a bioethicist at Columbia University and author of the book. say. baby designhe told me. A spokesperson for the American Society of Reproductive Medicine told me there is not enough high-quality data to express a view on whether such tests are useful. Last year, the American College of Medical Genetics and Genomics published a paper that said: long position statement It concludes that the benefit of screening embryos for polygenic risk is “unproven” and that the test “should not be offered as a clinical service.” The statement raised the possibility of people undergoing extra and unnecessary IVF in search of healthier embryos.
Published by Genomic Prediction rebuttal ACMG cited several studies led by corporate researchers that concluded, among other studies, that siblings with lower risk scores are significantly less likely to develop certain diseases. But the truth is that the effectiveness of screening embryos for polygenic risk is not clear until it is known whether the embryos selected to develop into fetuses are born, grow, and develop diabetes or not. That’s true. Genomic Prediction and Orchid both told me that humanity doesn’t have to wait that long for insights from testing. Polygenic risk scores are “one of the most valuable pieces of information available,” Orchid founder and CEO Noor Siddiqui told me. Nathan Tref, chief scientific officer at Genomic Prediction, was similarly bullish. “Everyone has some sort of family history of diabetes, cancer, heart disease, etc., so there’s really no situation where there’s no reason to get tested,” he told me.
Many experts I spoke to about these tests are concerned that people will choose IVF in search of certainty that companies can’t really promise. a I studied last year We found that there is both high interest and approval among Americans to screen embryos for polygenic risk. So far, most of the clients I’ve interviewed have been undergoing IVF anyway, so they’ve utilized advanced testing that includes polygenic risk. Many of Genomic Prediction’s customers who use the score are participants in clinical trials. But Tara Harandi Zadeh, an investor in Orchid, told me she and her husband are planning IVF, even though she and her husband have no history of fertility problems or genetic disorders. Harandi-Zadeh is particularly concerned about de novo mutations, or genetic changes that occur spontaneously without a genetic link. She wants to screen embryos to rule out monogenic diseases and plan for the risk of polygenic diseases. “With that information, we can help children access or prepare for treatment and testing at each stage of life,” she said. Treff said people like Harandi-Zadeh make up a small portion of Genomic Prediction’s customers, but the number is growing.
Scientists don’t know enough about the genome to predict with confidence what a single fetus will become if it becomes a person. Most genes influence many aspects of our existence, including our health, physical characteristics, and personality, but only a small portion of their interactions have been studied. “We don’t know the complete package,” Kritzman said. “Bipolar disorder is associated with creativity, so screening for bipolar disorder might also mean screening for genes related to creativity, for example.” No fetus is completely risk-free, so parents-to-be may need to decide whether they think the risk of diabetes or heart disease, for example, is worse. paper It came out last week “Even if clinical, ethical, and social concerns are ignored, the expected reduction in disease risk is modest at best.”
Those concerns are serious. Already, an increasing number of people are seeking IVF treatment for reasons other than infertility. Some people choose their children based on sex. Jeffrey Steinberg, a fertility doctor with clinics in the U.S. and abroad, told me he suggests eye color choices and works on height adjustments. Orchid assesses genetic risk for some people autism spectrum disorderGenomic Prediction plans to add similar screenings to its catalog. a paper A paper published last week argues that editing embryos, rather than just testing them, can reduce genetic risk for a variety of diseases, but also says it could “further exacerbate health disparities.” I admitted it. (In the United States, embryo-editing clinical trials are not approved by the FDA, and public funds cannot be used for research that edits embryos.) Critics argue that even if technology can reduce the spread of diseases such as diabetes, He argues that even if it were possible to do so, the possibility would be lost. It promotes discrimination against people born with such “undesirable” characteristics. Similar concerns have been raised in Iceland, where pregnancy tests have all but eliminated births with Down syndrome.
Even if science catches up to the ambitions of companies like genomic prediction, genetics will never guarantee a healthy life for a child. “Of the 100 things that can happen to a baby, more than 90 percent are not genetic,” Hank Greeley, director of Stanford University’s Center for Law and Life Sciences, told me. That’s part of the reason the Cassidys decided to ignore most of the screening results and simply select embryos that don’t carry Jamie’s single gene mutation and have the lowest risk of diabetes. “We’re not trying to have a 6-foot-2, blonde-haired, blue-eyed Harvard-bound kid. We just want a healthy baby,” Brennan told me. .
Their son was born in 2023 and has so far topped all developmental indicators. He spoke and walked quickly. It will probably be years before we know if he has diabetes. But they say it’s hard not to feel like they picked the right embryo.
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