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When Jennifer Leyton was going through IVF, her doctors would tell her very little. They turned off the ultrasound screen facing her so she could not count the number of eggs retrieved. They kept secret the number of fertilized embryos. They did not even say how many they transferred to her womb. This secrecy might have been maddening for many IVF patients, but for Leyton, it was her choice.

She chose secrecy because she wanted to avoid finding out whether she had inherited a mutation for Huntington’s. The neurological disease usually manifests between ages 30 and 50—with a jerky movement, or a slurred phrase—and progresses as the cells in the brain slowly die. She was still healthy, but her chances of having inherited her mother’s Huntington’s mutation were 50-50. Over a decade and a half, Leyton had watched as her mother’s hands became unsteady, dropping cigarettes that set her clothing on fire. She lost her driver’s license. She eventually stopped walking. The disease is always fatal.

Leyton did not want this fate for her future children. So she found a fertility clinic three states away that would perform in vitro fertilization, screen the resulting embryos for the Huntington’s mutation, and transfer only the healthy ones. Lastly, because she might deduce whether she herself carried the mutation by comparing the number of embryos fertilized with the number transferred, the clinic would give her none of the usual updates during the IVF process.

“I didn’t want to spend my time calculating whether or not I had the gene,” she says. She was okay with the secrecy. She was okay with undergoing IVF—even though she could have kids naturally if she got tested and found out she was negative for the Huntington’s mutation. But getting tested meant a 50-50 chance of finding out she was positive. She couldn’t risk that.

Not wanting to know is quite common among people at risk for Huntington’s. A genetic test that predicts almost perfectly whether someone will develop the disease has been available since the late 1980s, but only 8 percent of people at risk choose to test, according to the Huntington’s Disease Society of America. There is currently no cure for Huntington’s, and very little can be done for anyone with the disease. All someone at risk for Huntington’s might gain is certainty of how he or she will die. For this reason, a niche IVF market has sprung up for people like Leyton who want no foresight of their own future but want to keep their children from ever worrying about the disease.

After creating embryos through IVF, a patient can choose to screen them through a procedure called nondisclosure preimplantation genetic testing for monogenic disorders, or PGT-M. (It is also sometimes called preimplantation genetic diagnosis or PGD.) Most people who get PGT-M for Huntington’s are already aware of their status, and do not want to pass on the risk to their children.

Nondisclosure PGT-M is for people who do not want to know their status. These procedures are quite rare, but they exist in possibly one of the most unusual corners of modern medicine—where information is deliberately kept from the patient.


Leyton was one of the first people to undergo nondisclosure testing for Huntington’s in the late 1990s. She was living in New York at the time, but the only clinic she could find offering the procedure was the Genetics & IVF Institute in Fairfax, Virginia. She and her husband got extremely familiar with the drive down from New York. To monitor her hormone levels in between, she would regularly get her blood drawn in New York City and FedEx it to Fairfax. “You would have thought I was the dumbest person on Earth,” she says of having to mail her blood to Virginia. “All I wanted was to have a baby.” She ultimately had healthy twins, a boy and a girl.

Leyton chose what’s called direct nondisclosure testing, in which doctors would find out her Huntington’s status but keep it from her. Doctors at the Genetics & IVF Institute first proposed using this type of testing for Huntington’s in a 1996 paper. It was controversial, especially in Europe. Physicians there objected particularly to mock transfers, in which the fertility clinic still pretends to implant embryos, even if none of the resulting embryos are free of the Huntington’s mutation. To skeptics, this scenario captured the extreme lengths necessary to maintain nondisclosure.

Ultimately, says Harvey Stern, Leyton’s former doctor and the director of reproductive genetics at the Genetics & IVF Institute, his clinic only performed mock transfers once or twice, out of 40 to 50 total cases of direct nondisclosure testing for Huntington’s. In the early 2000s, doctors started routinely testing embryos for unrelated chromosomal abnormalities. Once they had a reason other than Huntington’s to screen out embryos, ending up with zero implantable ones was no longer so suspicious. Mock transfers were no longer necessary.

But Stern and his colleagues still had to establish other rules to make sure that the medical team did not accidentally reveal a patient’s Huntington’s status. Only Stern and people working in the lab had that information. The IVF doctors, nurses, and ultrasound technicians interacting directly with the patient did not. Nothing about genetic testing for Huntington’s even went into the patient’s chart; all of the paperwork was kept locked in a safe in the office of the then–lab director, Gary Harton.

All this secrecy changed the usual dynamic between the medical team and the patient. “With any other IVF cycle, they’re constantly getting updates,” Harton says. “Patients really live and die by that stuff. But in this case, it was completely the opposite, which was quite odd and difficult for everyone.” Nurses and ultrasound technicians who might otherwise make an encouraging comment such as “It looks great” had to keep quiet, lest they give the wrong impression about the number of embryos or eggs.

Sometimes patients would change their mind. “I vividly remember where certain patients, after their [IVF] cycle, would call up and say, ‘I know I have the mutation—you can tell me.’ We didn’t foresee that happening,” Harton says. Even then, they didn’t tell. Patients normally have to undergo a psychiatric evaluation to even take a genetic test for Huntington’s, to make sure they can withstand the shock of bad news.  A strict protocol is followed. “I can certainly understand that,” says Stern, about the patients who change their mind. “But I don’t want to be the one to make them jump off the bridge.”

With direct nondisclosure testing, that tension always exists between the doctors who know and the patients who do not. For this reason, some patients choose indirect nondisclosure testing, also called exclusion testing, where even the lab technicians and doctors do not know the patient’s status.

This is accomplished by testing not the Huntington’s gene itself but specific DNA markers next to the gene. It also requires testing the grandparents on the side of the family affected by Huntington’s. If Grandma has Huntington’s, then she carries one faulty copy and one normal copy of the gene linked to the disease. Her daughter, the mother, inherits one copy from Grandma (either faulty or normal) and one copy from Grandpa (normal). When she has a child, she has a 50 percent chance of passing along either Grandma’s copy or Grandpa’s copy. So without actually knowing whether the mother had inherited the faulty copy or the normal copy from Grandma, doctors can just exclude all embryos with Grandma’s DNA markers. The advantage is that doctors have nothing to conceal, nothing to accidentally reveal.

The disadvantage is that the lab needs the affected grandparent’s DNA, and he or she might not be alive to give it. And if the patient had inherited the normal copy of the gene, clinics that discard any embryo with the grandmother’s DNA markers would be discarding healthy embryos. This could lead to additional IVF cycles if not enough healthy embryos make it through testing in the first cycle.


Since the chances of inheriting a sick parent’s Huntington’s mutation is 50-50, half the people choosing nondisclosure testing don’t actually have the mutation. If they are otherwise fertile, they could be having children naturally. They don’t need IVF at all. And the process of IVF, says Helena Kääriäinen, the former president of the European Society of Human Genetics, is very expensive and quite hard on a woman’s body. In other words, there are additional costs to nondisclosure testing, both financial and physical.

Stern says nondisclosure testing is ultimately about giving patients a choice not to know: “People have said, ‘How can you make people go through IVF when they do not need it?’ My answer has always been: ‘I’m not making anybody go through it.’”

Marissa, who is 39 and lives in Seattle, decided on indirect nondisclosure PGT-M, while her brother chose another option, called chorionic villus sampling. (The Atlantic agreed to use first names only in some cases, to avoid outing the health status of family members.) The sampling is done on fetuses 10 to 12 weeks old, and it reveals whether a fetus has the Huntington’s mutation. If it does, then the at-risk parent can conclude that he or she does as well. Marissa’s brother was able to have two Huntington’s-free children this way, with the understanding that any fetuses that tested positive could be aborted.

But Marissa realized she couldn’t face the possibility of learning she had Huntington’s and having to decide in that moment whether to have an abortion. “That was just a position that—for myself—I was not wanting to be in,” she says. As soon as she got engaged, Marissa started saving up so that she and her husband could afford the IVF cycles and nondisclosure PGT-M testing. She now has twin girls.

The unequal demands of IVF on the woman can also make it tricky for couples deciding on nondisclosure testing. Faye went through indirect nondisclosure testing in the U.K. to have her two children because her husband is at risk for Huntington’s. He was the one who first learned about IVF and nondisclosure testing, and he was the one who first pushed it. But Faye would be the one physically going through IVF, which requires multiple daily hormone injections and constant appointments.

“Initially I was refusing to do it,” she says. “It was a big shock to me.” The two of them went to a genetic counselor who explained the risks of the Huntington’s mutation, and that made Faye viscerally understand why her husband would not want to be tested for Huntington’s. She agreed to IVF and indirect nondisclosure testing. Their son was born after one round of IVF.

Then they tried to have a second child, which took one failed embryo transfer, another failed transfer, surgeries to examine why those transfers failed, a failed egg retrieval, another successful egg retrieval, and a transfer with a single healthy embryo, before she finally got pregnant. “It was honestly the most horrendous experience of my life, and it nearly destroyed me,” Faye says. After each failed procedure, she found it difficult to work. There were times, she admits, when she thought about how she might not have to go through all this if only her husband would get tested. “When I was very low, I didn’t even know I needed to do that. When those emotions settled, I still came back to protecting him, protecting me, protecting the family. You don’t need to know this.”

In the U.K., the National Health Service provides people at risk for Huntington’s disease with up to three rounds of IVF to have one healthy child. After Faye and her husband had their son, though, they had to pay out of pocket to conceive their second child. “She was my £33,000 baby,” says Faye. They could afford the cost, the equivalent of about $45,000, for multiple rounds of IVF. But most people cannot.

In the United States, most insurance does not cover the cost of IVF with any kind of Huntington’s testing, which together run on average $20,000 to $25,000. The HelpCureHD Foundation recently announced grants for parents who want the procedure but cannot afford it. The foundation’s founders, Allie LaForce and Joe Smith, revealed that they were going through IVF with indirect nondisclosure testing to have children. (LaForce is an NBA reporter for TNT, and Smith is a pitcher for the Houston Astros.) When I called her, LaForce was going through her second round of IVF. She had been traveling around the country for work with hormone injections in tow.

The couple was shocked when they discovered the cost of IVF with a Huntington’s test. “We could afford it,” said LaForce, “but no wonder nobody does it.” They hope to fund five families a year, and the foundation has also partnered with the Cleveland Clinic and the Houston Fertility Institute for discounted treatment. The foundation will fund any type of PGT-M for Huntington’s—disclosure, direct nondisclosure, or indirect nondisclosure—though LaForce and Smith themselves chose indirect nondisclosure testing.

They chose that option because Smith has never taken the Huntington’s test himself. He had seen how Huntington’s disease had taken over his mother’s life. When she could still go to his games, people would accuse her of being drunk because of her slurred speech. She now lives at a full-time care facility. “He just has watched his mom struggle,” said LaForce, “and I think it’s hard for him to imagine that is his life 10 to 15 years from now.” They don’t know whether their children will have to watch Smith struggle, but they do know that with IVF and preimplantation testing, their children will never have to imagine Huntington’s disease taking over their own lives.

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