Expanded Carrier Screening

What are universal carrier screening panels?

You may have heard of “universal” or “pan-ethnic” or “expanded” carrier screening panels, which are newer screening panels that test for 80+ genetic diseases that could occur in infancy or childhood, if both parents are shown to be carriers of the same disease. These panels are different from those that only test for genetic mutations associated with diseases common in the Ashkenazi Jewish population. The expanded panels are available due to advances in genetic testing methods and technologies, which has made it easy to add more and more diseases to panels without an increase in cost. Because of this, and because one’s true ethnicity is not always 100% clear, these larger panels are gaining popularity.

Is more really better?

Because “knowledge is power,” if one is found to be a carrier, then having been screened for more diseases would be considered “better.” “Carrier couples” can use the information when considering various options for building a healthy family, and carriers could also tell their relatives of their results since they share genetic material.

But, truth be told, many of the mutations on these expanded panels are not necessarily found in all ethnic groups or couples; they are not as “universal” as you might think. If you are tested for a mutation that is common in your ethnic background and you are found to be negative, then we can say with confidence that you are not a carrier (but there is always a slight possibility that you could be a carrier for a rare mutation). However, for diseases that are not common in your ethnic background, negative results will not significantly reduce your risk of being a carrier.

As with any screening test, a negative result on a broader screening does not fully eliminate the risk of having a child affected with one of the tested disorders, it only reduces the risk. Furthermore, expanded carrier screening does not cover all diseases that could affect offspring. Additional diseases (not covered on the panel) may run in the family, ultrasounds may suggest the presence of other diseases, and genomic (chromosomal) disorders will not be picked up by universal carrier screening.

Should I consider expanded carrier screening?

It is up to you. For the Ashkenazi Jewish population, current professional guidelines recommend preconception carrier screening for diseases that are commonly found in this population, in addition to spinal muscular atrophy and (in some cases) fragile X syndrome. There are currently no professional guidelines to recommend the use of large expanded panels for carrier screening, although the updates on these guidelines may be forthcoming.

All this being said, if you would like to find out more about the possibility of expanded carrier screening, we recommend that you meet with a genetic counselor.