may have to make different reproductive decisions. But she may not know what her options are if she is found to be a carrier, and she may not be aware that options exist. Also, she may not be expecting to receive genetic information about her own health, especially about conditions for which the implications are unclear and the significance unknown. Because of this lack of knowledge, pretest counseling is imperative, said Gilats.
Preconception screening to date has been determined mainly by ethnicity. But not everyone knows his or her ethnic background, and many people have mixed ancestry. This situation creates an advantage for larger screening panels because they are more universal in scope and reduce the need to rely solely on patients’ self-assessment of their ethnicity.
The Center for Jewish Genetics uses the Counsyl panel for testing but gives people the option of doing a more limited Ashkenazi panel for 18 conditions. Most people choose the larger panel because it provides more information at the same cost. The downside is that a large panel can provide too much information. For example, it can produce results for conditions that do not have clear-cut responses, such as hereditary hearing loss, or conditions or traits that are not lethal or may not be very life altering. “Yet, because people have the information, they [can] feel they need to act on it,” Gilats noted.
Gilats said that she used to work in prenatal genetics and often encountered patients who had maternal serum screening in pregnancy without being fully informed of the implications of possible results. When she would explain that the results indicated an increased likelihood of Down syndrome, patients could become angry because they had no intention of changing their pregnancy plans and would have refused the test if they had known what it might tell them.
Most patients have a poor understanding of genetics and the residual risk, said Gilats. Even in the well-educated population with which she works, the concept of residual risk for recessive disorders after carrier screening is often misunderstood. For instance, she recently told a patient that she was a carrier for a condition and that her husband was not, yet the patient was still not sure whether she should be concerned. Another patient, a doctor, was confused after being told that she and her husband still had a risk of having a child with cystic fibrosis even though she screened negative. And because many of these conversations occur in a clinical setting after a pregnancy occurs, rather than before conception, decisions made on the basis of this information can be even more difficult.
This lack of understanding will only be exacerbated with whole genome screening, said Gilats. It will not be possible to educate people about all the different disorders and results that are possible. Rather, explanations will have to be broad, outlining categories and examples of results. Having whole genome information for the woman in this scenario, for