Team Outlines Paternal Sample-Free Single-Gene Approach for Non-Invasive Prenatal Screening

In Genetics in Medicine, a team from the California firm BillionToOne and the University of North Carolina School of Medicine outline a reflex single-gene non-invasive prenatal testing approach that is feasible in the absence of accompanying paternal samples. In almost 9,200 pregnant participants in an unselected group from the US population, the researchers found that 1,669 of the mothers-to-be carried a copy of at least one pathogenic variant linked to the recessive conditions considered: cystic fibrosis, spinal muscular atrophy, alpha-hemoglobinopathies, or beta-hemoglobinopathies. With the single-gene non-invasive prenatal screening (sgNIPS) approach, they got informative results in all but 1.3 percent of cases, successfully uncovering affected pregnancies with an average positive predictive value of more than 48 percent with sgNIPS. "We found that carrier screening with sgNIPS is a more effective alternative to traditional carrier screening when a person is pregnant," the authors report, "with clear benefits of identifying high-risk fetuses and providing tailored sgNIPS fetal risks in a timely manner without the need for a paternal sample."