Study identifies potential biomarker for SIDS, but a test for it is a long way off

Experts say the new study is interesting but urge caution about interpreting the findings.

(CNN)Australian researchers say they've identified one potential biomarker for sudden infant death syndrome, known as SIDS, but experts caution that it's just one piece of the puzzle.

About 3,400 babies die from SIDS in the US each year. There is no immediate or obvious cause of death, according to the US Centers for Disease Control and Prevention. Experts don't know which babies are at risk for SIDS or what causes it.
For their study, published May 6 in the journal eBioMedicine, the researchers measured levels of an enzyme called butyrylcholinesterase (BChE) in blood samples from 67 newborns who died of SIDS and other unknown causes between 2016 and 2020. They compared these levels with those in the blood of 655 babies in a control group and found that the children who died of SIDS had significantly lower BChE levels than living children or those who died of other causes.
    SIDS usually happens when a child is sleeping. Experts have speculated that it's associated with problems in the part of an infant's brain that controls breathing and waking. BChE is an enzyme of the cholinergic system, part of the autonomic system, which controls functions like blood pressure and breathing. The study authors say more research is needed to determine whether BChE tests might be able to identify and prevent future SIDS cases.
      Smoking during pregnancy is one of the risk factors for SIDS, along with things like family history and premature birth. The researchers noted that animal studies have shown a tie between secondhand smoke and lower BChE. However, many other changes in the first six months of life are also likely to affect these enzymes and the nervous system in general.
      The researcher who led the study, Dr. Carmel Harrington, an honorary research fellow at the Children's Hospital at Westmead in Australia, lost her own child to SIDS 29 years ago, according to the Sydney Children's Hospitals Network.
      "Babies have a very powerful mechanism to let us know when they are not happy. Usually, if a baby is confronted with a life-threatening situation, such as difficulty breathing during sleep because they are on their tummies, they will arouse and cry out. What this research shows is that some babies don't have this same robust arousal response," Harrington told the network.
        Harrington said this study shows that BChE is involved with this lack of arousal.
        "Now that we know that BChE is involved, we can begin to change the outcome for these babies and make SIDS a thing of the past," she said.