NEW RESEARCH OFFERS CLUES AS TO WHY SOME BABIES DIE OF SIDS

Scientists in Australia have found that some babies at risk of sudden infant death syndrome, or SIDS, have low levels of an enzyme called butyrylcholinesterase (BCHE) in their blood. Their study, published May 6 in the journal ebiomedicine, could pave the way for newborn screening and interventions if the results are corroborated by further research.

“It’s the first time we’ve ever had a potential biomarker for SIDS,” said Dr. Carmel Harrington, who led the research at the Children’s Hospital at Westmead in Sydney.

Researchers have been trying to chip away at the biological underpinnings of the puzzling syndrome for decades. And while public health campaigns have drastically reduced the incidence of SIDS, it remains a leading cause of sudden and unexpected death in infants under the age of 1 in Western countries.

In the United States, about 3,400 babies die suddenly and unexpectedly each year, according to the Centers for Disease Control and Prevention. This includes infants who die suddenly from a known cause, such as suffocation, as well as those who die without a clear cause, such as from SIDS. Nearly half of the sudden and unexpected infant death (SUID) cases in the United States are due to SIDS.

One of the reasons that SIDS remains so mysterious is because it is probably not caused by a single biological mechanism but by a combination of factors that come together in a perfect storm, said

Dr. Thomas Keens, a pediatric pulmonologist at Children’s Hospital Los Angeles. Previous studies have pointed to low activity or damage in parts of infants’ brains that control heart rate, breathing and arousal from sleep, for instance, as well as to environmental stressors such as soft bedding or secondhand smoke.

To test if there was something inherently different in SIDS babies, Harrington and her colleagues compared dried blood samples from the newborn heel prick test of 655 healthy babies, 26 babies who died from SIDS and 41 babies who died from another cause. They found that about nine out of 10 babies who died of SIDS had significantly lower BCHE levels than did the babies in the other two groups.

“I was just stunned,” said Harrington, who has been searching for clues and crowdfunding for her research for nearly 30 years since she lost one of her children to SIDS. “Parents of SIDS babies carry a huge amount of guilt because essentially their child died on their watch. But what we’ve found with this study is that these infants are different from birth, the difference is hidden, and nobody knew about it before now. So it’s not parents’ fault.”

The new findings add support to researchers’ hypothesis that babies who die from SIDS have problems with arousal, said Dr. Richard Goldstein, a pediatric palliative care specialist at Boston Children’s Hospital. BCHE plays a role in the availability of important neurotransmitters in the brain’s arousal pathway.