A new study has identified a biomarker that could one day be used to help babies at higher risk of sudden infant death syndrome (SIDS).
The research, conducted by a team from Children’s Hospital Westmead (CHW) in Australia, was published in eBioMedicine.
Half of Western infant deaths caused by SIDS
Sudden infant death syndrome is defined as the death during sleep of a seemingly healthy infant of less than one year of age. Cases of SIDS have halved in recent years after high-profile campaigns that have highlighted some of the other risk factors for SIDS, including:
· Sleeping on their stomach or side
· One parent shares the same bed
· High temperature during sleep
However, SIDS remain the cause of nearly half of neonatal deaths in Western countries, and biochemical signatures explaining the risks of infants with this syndrome have been missing. The new study, led by CHW Research Fellow Dr. Carmel Harrington, hopes to change that.
Harrington and his team analyzed dry blood spots (DBS) taken during a newborn screening program, using samples that parents had agreed to analyze.
The study focused on an enzyme called butyrylcholinesterase (BChE). The enzyme has an important function in the wakefulness pathway, which controls the level of brain alertness during wakefulness. The team analyzed BChE levels in samples from four different groups:
· Infants who died from SIDS (n = 26)
· Infants who died of causes other than SIDS (n = 30)
· SIDS group controls – healthy children matched by date of birth and sex (n = 254)
· Non-SIDS group controls – healthy children matched by date of birth and sex (n = 291)
The SIDS group showed a significant decrease in BChE activity compared to matched controls, a finding not seen in non-SIDS mortality.
lack of vigilance
The team believes that the BChE deficit could indicate a decreased ability to wake up in response to stresses in the external environment. Harrington commented in a press release: “Usually, if a child experiences a life-threatening situation, such as difficulty breathing while sleeping because they are on their stomachs, they will wake up and scream. What this research shows is that some children do not have the same strong arousal response.”
Harrington, who tragically lost her son Damian to SIDS nearly 30 years ago, said the discovery points to a brighter future for children at risk for SIDS. “This has long been thought to be the case, but until now we didn’t know why there was such a lack of excitement. Now that we know BChE is involved, we can start to change the outcome for these children and make SIDS a thing of the past,” she said.
However, the small sample size is an indication that research is still at an early stage and parents are still encouraged to take steps to reduce environmental risk factors for SIDS. The CHW Child Health Promotion Unit says that children should be laid on their back to sleep with their head and face uncovered during the night. In addition, the child’s family must be smoke-free.
The next step for the research is a five-year study that will integrate the BChE biomarker into newborn screening. The team plans efforts to mitigate the biochemical effects of the enzyme deficiency.
Harrington, who has funded much of her research through a campaign called Damien’s Legacy, concluded, “This discovery changes the narrative around SIDS and is the beginning of a very exciting journey into the future. We will be able to work with children during their lives and make sure they continue to live.”
reference: Harrington CT, Hafid NA, Waters KA. Butyrylcholinesterase is a potential biomarker of sudden infant death syndrome. eBioMedicine. 2022; 80: 104041. doi: 10.1016/j.ebiom.2022.104041