Recommendations for management of positive monosomy X on cell-free DNA screening
Non-invasive prenatal testing (NIPT) using cell-free DNA (cfDNA) is currently offered to all pregnant women regardless of the fetal risk. While this test has excellent value to screen for chromosomal abnormalities such as Down syndrome, the test has a much lower positive predictive value for sex-chromosome abnormalities such as Turner syndrome. In a study published in the American Journal of Obstetrics and Gynecology, researchers provide context and expert recommendations for maternal and fetal evaluation and management when cfDNA screening is positive for monosomy X or Turner Syndrome (TS).
The manuscript was put together by the Turner Syndrome Special Interest Group (TS SIG) of the Pediatric Endocrine Society, chaired by Roopa Kanakatti Shankar, M.D., endocrinologist at Children’s National Hospital, along with other specialists including a gynecologist, maternal fetal medicine expert, cardiologists and pediatric endocrinologists.
The big picture
The field of NIPT using cfDNA testing has advanced considerably making it routine in the care of pregnant women and more couples are opting for it. This will lead to an increased detection of monosomy X overall — some of which may be true positives, but others may be false positives, or even an indicator of maternal TS rather than an affected fetus. This article discusses the changing landscape and provides an expert opinion on how to manage these scenarios.
How does this work move the field forward?
“We hope that this will increase provider knowledge and recognition of the pitfalls of NIPT as a screening test for sex-chromosome disorders such as monosomy X,” says Dr. Kanakatti Shankar. “It will also provide a framework for the next diagnostic steps, management and referrals that a provider may take to optimize care for both mother and child.”
How is Children’s National leading in this space?
Current guidelines for the care of individuals with TS throughout the lifespan do not specifically address management of individuals with a cell-free DNA screen positive for monosomy X.
“As chair of the TS Special Interest Group, I was able to lead this unique collaborative effort which we hope will lead to better understanding of NIPT results in the context of TS and for multispecialty providers to improve prenatal detection and timely care,” says Dr. Kanakatti Shankar.
Read more about the study, Cell-free DNA screening positive for monosomy X: clinical evaluation and management of suspected maternal or fetal Turner syndrome.