Breakthrough Discovery Identifies Biochemical Marker for Infants at Risk of SIDS

Analysis shows the activity of a specific enzyme, Butyrylcholinesterase, was significantly lower in those who subsequently died of sudden infant death syndrome.

Investigators at the Children’s Hospital at Westmead in Australia have identified the first biochemical marker that could help detect more infants at risk of sudden infant death syndrome (SIDS), the unexplained death of an apparently healthy infant younger than 1 year of age while they are sleeping..

In the study, published by eBioMedicine, investigators found that the activity of a specific enzyme, butyrylcholinesterase (BChE), was significantly lower in infants who subsequently died of SIDS compared with the living controls and other infants’ deaths.

Investigators analyzed BChE activity in 722 dried blood spots taken at birth as part of the Newborn Screening Program, using only samples parents approved for use in de-identified research. BChE was measured in both infants with SIDS and infants who died from other causes. Each individual infant was compared with 10 surviving infants with the same date of birth and gender.

Additionally, investigators found that infants with lower BChE levels had a higher risk of dying from SIDS. Because BChE plays a role in the brain’s arousal pathway, investigators think its deficiency likely indicates an arousal deficit, which reduces the infant’s ability to respond to the external environment or wake, making them vulnerable to SIDS.

“An apparently healthy [infant] going to sleep and not waking up is every parent’s nightmare, and until now there was absolutely no way of knowing which infant would succumb, but that’s not the case anymore. We have found the first marker to indicate vulnerability prior to death,” Carmel Harrington, PhD, LLB, BSC, DIPED, honorary research fellow at CHW said in a statement.

“This has long been thought to be the case, but up to now we didn’t know what was causing the 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,” Harrington said.

The discovery has opened the possibility for intervention and gives answers to parents who have lost their children in this way, she said.

The incidence of SIDS has been more than halved in recent years because of health campaigns addressing the known major risk factors of maternal smoking, overheating, and prone sleeping in a prone position, according to the statement.

However, the rate of SIDS remains high and contributes to almost 50% of all post-neonatal deaths in the Western countries.

The triple-risk model has been used to explain the occurrence of SIDS deaths. It hypothesizes that 3 factors, including a vulnerable infant, a critical developmental period, and an exogenous stressor, must occur simultaneously to cause SIDS, but there was never a way to identify those infants.

The identification of the BChE biochemical marker gives investigators a direction for future research, helping them focus on introducing this marker into newborn screening and developing specific interventions to address the enzyme deficiency.

Investigators estimate that the next stages of research will take approximately 5 years to complete.

Reference

World-first breakthrough could prevent SIDS. Kids Research. News release. May 9, 2022. Accessed May 13, 2022. http://www.kidsresearch.org.au/news/world-first-breakthrough-could-prevent-sids