Landmark Study of Nearly 350,000 Patients Finds Expanded Prenatal Genetic Testing Could Increase Detection of Risk for Serious Inherited Diseases

Counsyl announces publication of the largest, most ethnically diverse genetic study on Expanded Carrier Screening in the Journal of the American Medical Association (JAMA)

SAN FRANCISCO--()--Counsyl, a DNA testing and genetic counseling service, today announced a new study published in the Journal of the American Medical Association (JAMA), which concludes that expanded carrier screening (ECS) may significantly increase the detection of carrier status for severe genetic conditions as compared to current screening guidelines.

In a joint statement issued last year, several medical societies requested further research to better quantify the clinical impact of ECS across ethnic groups. This study answers that call, and provides important new data to support the further examination and potential adaptation of screening guidelines.

The study, titled “Modeled Fetal Risk of Genetic Diseases Identified by Expanded Carrier Screening,” examined DNA test results of nearly 350,000 individuals, spanning 15 ethnicities, to assess the prevalence of genetic variants associated with 94 severe or profound inherited genetic conditions. Severe conditions are defined as causing intellectual disability or a substantially shortened lifespan; profound conditions cause both.

Current guidelines, which typically recommend testing for a small number of conditions in patients of select ethnicities, are tailored to those of a particular ethnic background or those with a family history. Broader implementation of ECS is now possible because of advanced technology, and the study shows that ECS could benefit today’s diverse population.

“Even though the guidelines target a number of diseases prevalent in those of European descent (such as cystic fibrosis), they do not identify risk for other conditions that may be important to diverse populations. Expanded carrier screening revealed that many non-European racial/ethnic categories have a risk of profound or severe genetic disease that may not be detected by the guidelines in place at this time of analysis,” the authors write.

Data in the study demonstrates that across ethnic groups, a significant percentage of pregnancies affected by serious conditions may not have been detected under current screening guidelines set by the American College of Obstetricians and Gynecologists (ACOG) and the American College of Medical Genetics and Genomics (ACMG).

When results of the study are calculated in aggregate and weighted by US census demographics, approximately one in 550 pregnancies would be affected by a serious condition on the Family Prep Screen (the expanded carrier screen used in the study). This is comparatively higher than the known incidence of routinely screened-for conditions such as Down Syndrome, which has an incidence of one in 700 births.

“This research quantifies the clinical impact of expanded carrier screening, and demonstrates a significant opportunity to identify more pregnancies affected by serious genetic conditions,” said Imran Haque, PhD, VP, Scientific Affairs at Counsyl and lead author on the study. “Counsyl is committed to sharing insights with the scientific and medical communities based on our clinical experience of over half a million carrier screens. We hope this will drive forward the conversation on broader integration of screening for patients of all ethnicities.”

Authors of the study include Imran Haque, PhD, Gabriel Lazarin, MS, Peter Kang, MD, Eric Evans, PhD, James Goldberg, MD (Departments of Medical Affairs and Research, Counsyl) and Ronald Wapner, MD (Division of Reproductive Genetics, Department of Obstetrics and Gynecology, Columbia University Medical Center).

The study can be accessed here: Modeled Fetal Risk of Genetic Diseases Identified by Expanded Carrier Screening

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About Counsyl

Counsyl is a DNA testing and genetic counseling service. We're committed to helping patients understand their DNA and how it can inform important health decisions. Whether it’s starting a family or evaluating risk for cancer, Counsyl's DNA tests provide patients with early awareness about genetic conditions, so they can live informed and prepare for the future. Counsyl has screened more than 600,000 patients and served more than 10,000 health care professionals.

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Andrew Padgett


Andrew Padgett