Australian Researchers Discover First Biomarker for Sudden Infant Death Syndrome

A team from The Children’s Hospital at Westmead, Australia identified a potential blood biomarker that could be utilized for spotting infants at risk of sudden infant death syndrome (SIDS). While exact SIDS factors remain unspecified, the researchers theorized that SIDS low levels of butyrylcholinesterase (BChE) enzyme in blood could be a contributing factor.

SIDS is the unexplained death of seemingly healthy infants during sleep periods, typically in children less than 1-year-old. It is believed that SIDS is not due to multiple factors, despite extensive research, the identification of any specific mechanism remained elusive. In the US, there are around 1,300 SIDS cases reported each year and are trending down thanks to intensive health campaigns.

The study published in The Lancet’s eBioMedicine analyzed BChE activity in over 700 Dried Blood Spots (DBS) taken at birth from 2016 to 2020, with parents’ approval for de-identified research use. BChE was measured in both SIDS and infant deaths from other causes, and each sample compared to 10 surviving infants with the same birth date and gender.

“This discovery has opened up the possibility for intervention and finally gives answers to parents who have lost their children so tragically. These families can now live with the knowledge that this was not their fault,” said lead researcher Dr. Carmel Harrington.

Related article: Sudden Death in Infants Could Have a Genetic Basis 

BChE’s Role in Brain Arousal

Acetylcholine (ACh) is a major neurotransmitter in the autonomic nervous system and is the principal neurotransmitter of the parasympathetic nervous system, it is hydrolyzed by acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) to regulate nervous activities. Low levels of BChE could indicate brain’s reduced ability to signal baby to wake or respond to external environment, eg. wake up and turn head or gasp for breath, increasing vulnerability to SIDS.

While the study identified an important biomarker in a small group of infants, it is too soon to determine if widespread testing for BChE will help reduce deaths. It is crucial to confirm whether decreased BChE activity in peripheral blood is also observed in the brain due to BChE’s possible role in maintaining acetylcholine levels.

The function of BChE is not well understood, including what is the enzyme’s “normal” level, and growing research has now led to targeted studies on BChE, for example as a potential treatment target in Alzheimer’s disease. Dr. Harrington’s next step is to begin looking at introducing BChE biomarker screening for newborns and develop specific interventions to address the enzyme’s deficiency.

American Academy of Pediatrics recommends a safe sleeping environment such as avoidance of soft beddings and overheating, and encourages breastfeeding, routine immunization, and use of a pacifier to reduce SIDS risk.

Author

Fujie Tham