NEW YORK (GenomeWeb) – Commercial preconception carrier screening is currently prohibited in the Netherlands and there are no guidelines for such sequencing-based tests, but that may soon change, depending on the outcome of a study conducted by researchers at the University Medical Center Groningen.
A group led by Irene van Langen, a professor of clinical genetics at the University Medical Center Groningen and head of the ethical, legal, and social issues in genetics program there, has developed a next-generation sequencing-based preconception carrier screening test that includes 50 serious, early-onset, untreatable conditions. The researchers are now running a pilot study, offering the test through 15 general practitioners in the northern Netherlands, and plan to survey couples who decide to take the test as well as those who do not over the next year or two.
Earlier this month, the researchers published the results of an initial survey in the European Journal of Human Genetics that asked about potential users' preferences for carrier screening, including the types of diseases they would want testing for, how they would prefer to receive the test and results, and how much they would be willing to pay for it.
"We were positively surprised that about one-third of respondents intended to take the test," Mirjam Plantinga, lead author of the study and a postdoctoral genetics researcher at the University Medical Center Groningen, told GenomeWeb.
For the survey, the team recruited men and women between the ages of 18 and 40 who had a partner, since the test would not be offered to individuals, but couples. Of 869 individuals who met the criteria, 504 completed the survey, with a mean age of 29 years.
About one-third of the respondents said they would take the test if it was offered, 15 percent said they were not likely to take the test, and 51 percent said they were undecided.
Younger respondents were more likely to be undecided, while religious respondents tended to be unlikely to take the test.
Respondents said the primary reason for getting carrier screening was to avoid having a child with a serious hereditary disease, while the second most important reason was to be able to prepare. The most cited reason against testing was that respondents did not want to know, followed by the potential for such testing to have negative consequences on the relationship, and being against genetic testing as a means for making reproductive decisions in general.
The majority of respondents, 44 percent, thought a carrier screening test should be offered by a general practitioner as opposed to a clinical geneticist, gynecologist, direct-to-consumer company, or other potential options.
"They didn't favor a clinical geneticist in a hospital to be the one to inform them of the test because they thought they would be more likely to encourage them to take the test compared to a general practitioner," van Langen said.
The researchers also found that while the respondents favored the current test, which covered serious, untreatable conditions, more than half were also interested in getting carrier screening for serious and treatable conditions, as well as serious and late-onset conditions. Only 19 percent were interested in knowing results unrelated to health.
Those preferences could help the researchers decide whether and how to expand the existing panel beyond the current 50 diseases. For instance, the panel does not cover cystic fibrosis, van Langen said, because it is included in the Dutch newborn screening program, so it did not meet the group's original criteria when deciding which diseases to include on a panel. In future discussions, she said, researchers would consider whether to include cystic fibrosis and perhaps some other diseases.
The situation in the Netherlands is very different from the US, for instance, where the American College of Obstetrics and Gynecologists recommends that cystic fibrosis carrier screening be offered to all women. In addition, even expanded carrier screening tests that assess the risk for multiple diseases are available from companies like Counsyl, Good Start Genetics, GenePeeks, and others in the US, which has not been the case in the Netherlands, where carrier screening is prohibited.
Van Langen said one goal of the current study was to engage stakeholders to figure out what responsible carrier screening looks like and what diseases should be included in the panel.
Since January, 15 general practitioners have been offering the panel to their female patients and partners. Couples are surveyed before and after taking the test, and also when they decline testing, so that researchers can get an idea of why they decided against it.
"It's important to know what the uptake is, whether couples are able to make informed decisions and what the psychological impact is," Plantinga said.
The group will also study the feasibility of implementing carrier screening in a general practitioner setting, for example whether the clinician has enough time to sufficiently educate patients about the test and provide appropriate pre-test counseling to facilitate informed choices. Prior to offering the test, the general practitioners also received training on pre-test counseling from the genetics department.
The initial study is geared toward heterosexual couples, but the researchers next plan to study individuals looking to have a child via a sperm or egg donor. "We want to compare whether there are differences in attitudes and intentions with preconception carrier screening," Plantinga said. In addition, patients may also have friends or relatives as a donor, which makes the question even more complicated, she added.
The researchers plan to publish additional studies on the preconception carrier screening test, focusing on different factors that explain couples' decisions to pursue testing and whether the way information is presented impacts how couples make choices. For instance, they will ask if reporting a risk as a 1 in 100 chance of being a carrier couple versus a 99 in 100 chance of not being a carrier couple impacts a couple's choice.
Finally, an important factor to consider is the cost of the test and who will pay for it. In the EJHG study, of the respondents who said they would be willing to take the test, 58 percent said they would be willing to pay for it, with their maximum amount ranging from €5 to €5,000. The median amount was €75. Van Langen said that the cost of running the current panel is €800 per couple, which does not include personnel or genetic counseling costs.
In the ongoing implementation study, the test is being offered free of charge, van Langen said, but the ultimate goal is to have it reimbursed by insurance or included as part of a national screening program.