New syndrome in newborns exposed to fentanyl possibly found

At least 10 babies — possibly more than 12 — have been identified with what doctors believe to be a new syndrome related to exposure to fentanyl in the womb.

All of the infants have distinctive physical birth defects, such as cleft palate and unusually small heads. No common genetic cause has been uncovered — all were born to mothers who said they'd used street drugs, particularly fentanyl, while they were pregnant.

Six babies were identified at Nemours Children's Health in Wilmington, Delaware, two in California and one each in Massachusetts and Rhode Island. Erin Wadman, a genetic counselor at Nemours, and her colleagues published their findings recently in Genetics in Medicine Open.

The aha moment linking the infants came in August 2022, when Wadman was called upon to consult in the case of a baby who'd been born with birth defects. "I was sitting there in the appointment, and I was just like this face looks so familiar. This story sounds so familiar. And I was just thinking about how this patient reminded me so much of a patient I'd seen earlier in the year and then other patients I'd seen," Wadman said. "That's when we were like we think we might have stumbled on something really big here."

In addition to cleft palate, the 10 infants have unusually small bodies and heads. They tend to have drooping eyelids. Their noses tend to turn upward, and their lower jaws are often undersized. Their feet may point down and inward, and two of their middle toes are webbed. Baby boys may have genital irregularities. Some have trouble feeding, and their thumbs may not be fully formed. The physical similarities reminded Wadman and a Nemours colleague, Dr. Karen Gripp, a geneticist, of a syndrome called Smith-Lemli-Opitz. In those cases, genetic variants affect how fetuses process cholesterol, which is necessary for normal cell function and brain development.

Read the full story on NBCNews.com.