Decisions about who should be screened for certain inherited conditions may hinge heavily on the patient’s self-reported ethnicity.
However, a new study by 23andMe researchers found that these ethnicity-based guidelines miss more than half of those who are carriers for some serious genetic conditions.
Carrier Status Testing
Some medical societies, including the American College of Obstetricians and Gynecologists (ACOG), have traditionally recommended ethnicity-based carrier screening for specific inherited conditions. For example, for people reporting Ashkenazi Jewish ancestry, they recommend screening for such as Bloom syndrome and Gaucher disease. For those with Ashkenazi ancestry or French Canadian or Canjun ancestry, they recommend screening for Tay-Sachs disease. However, many people may not know their ancestry or may not report their ancestry to their healthcare providers.
This new study, published in the journal Genetics in Medicine Open, found that more than half of the carriers of these conditions, 54.9 percent, did not report Jewish or Ashkenazi Jewish ancestry. In other words, they either do not know or do not report having Ashkenazi Jewish ancestry, which is one of the criteria for ACOG ethnicity-based screening guidelines. About half of all carriers had less than 20 percent Ashkenazi Jewish genetic ancestry. This underscores the inadequacy of relying solely on self-reported ethnicity or genetic ancestry for carrier status screening.
“Our research suggests that many individuals who are carriers for one of these inherited conditions are being missed under current ethnicity-based screening criteria,” said Dr. Noura Abul-Husn, VP of Genomic Health at 23andMe and senior author of the study.
Criteria Misses Many at Risk
Carrier screening has long been a crucial tool for identifying genetic conditions inherited in an autosomal recessive or X-linked manner. Some of these inherited conditions are also much more common in some ethnicities than others.
It’s estimated that about one in three people of Ashkenazi ancestry are carriers for 16 genetic disorders more common in that population. For many years, screening recommendations from the ACOG and others have suggested that people of Ashkenazi descent be screened for many of these conditions.
For this study, 23andMe researchers analyzed the self-reported ethnicity and genetic ancestry of over 7.2 million 23andMe customers who consented to participate in the research. The scientists then identified 116,517 individuals who were carriers of inherited conditions for which ACOG recommends carrier screening in the Ashkenazi Jewish population.
More than half of those carriers, 54.9 percent, did not report Jewish ethnicity, which is one of the ACOG ethnicity-based screening guidelines criteria.
Moving Beyond Ethnicity-Based Screening
These findings have profound implications. This work is consistent with previous research that has demonstrated that ethnicity-based carrier screening can result in the under-detection of carriers.
Another medical society, the American College of Medical Genetics and Genomics (ACMG), issued guidelines in 2021 recommending that healthcare providers not use ethnicity to guide carrier screening. Instead, the ACMG recommended screening everyone using the same tiered approach. However, some insurance companies do not provide coverage for this type of carrier screening. Those insurers cite ACOG ethnicity-based carrier screening as a justification.
Knowing carrier status allows prospective parents to make informed decisions regarding family planning, like pursuing in vitro fertilization with genetic screening or preparing for the birth of a child with a genetic condition. Moving beyond ethnicity-based carrier screenings, we can improve the detection of carriers and better assess reproductive risks, ultimately leading to more informed and effective healthcare decisions.
This research calls for reevaluating current guidelines and shifting towards more inclusive and comprehensive genetic screening approaches that do not rely on self-reported ethnicity.
Learn More
23andMe’s Health & Ancestry Service includes reports on more than 45 inherited conditions, including cystic fibrosis, sickle cell anemia, and Tay-Sachs disease.
Find out more about all that 23andMe has to offer here.
